C# Online Compiler | .NET Fiddle

using System;
using System.ComponentModel.DataAnnotations;
using System.Collections.Generic;

namespace HelloWorldMvcApp
{
	public class SampleViewModel
	{
		public List<CarouselItemModel> CarouselItemList
		{
			get;
			set;
		}
	}

	public class CarouselItemModel
	{
		public string Title
		{
			get;
			set;
		}
		
		public string Alt
		{
			get;
			set;
		}

		public string ImagePath
		{
			get;
			set;
		}
	}
}

@model HelloWorldMvcApp.SampleViewModel
@{
	Layout = null;
}

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Bootstrap 4 Carousel</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js"></script>
<style>
.carousel{
    background: #2f4357;
    margin-top: 20px;
}
.carousel-item{
    text-align: center;
    min-height: 280px; /* Prevent carousel from being distorted if for some reason image doesn't load */
}
</style>
</head>
<body>

<div class="container-lg my-3">
    <div id="myCarousel" class="carousel slide" data-ride="carousel">
        <!-- Carousel indicators -->
        <ol class="carousel-indicators">
            <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
            <li data-target="#myCarousel" data-slide-to="1"></li>
            <li data-target="#myCarousel" data-slide-to="2"></li>
        </ol>
        <!-- Wrapper for carousel items -->
        <div class="carousel-inner">
			@if (Model.CarouselItemList.Count() > 0)
			{
				for (int i = 0; i < Model.CarouselItemList.Count - 1; i++) 
				{				
					if (@Model.CarouselItemList[i] == Model.CarouselItemList[0]) 
					{
						<div class="carousel-item active">
						 <img src="@Model.CarouselItemList[i].ImagePath" alt="@Model.CarouselItemList[i].Alt">
						</div>
					}
					else 
					{
						<div class="carousel-item">
							<img src="@Model.CarouselItemList[i].ImagePath" alt="@Model.CarouselItemList[i].Alt">
						</div>
					}
				}
			}
        </div>
        <!-- Carousel controls -->
        <a class="carousel-control-prev" href="#myCarousel" data-slide="prev">
            <span class="carousel-control-prev-icon"></span>
        </a>
        <a class="carousel-control-next" href="#myCarousel" data-slide="next">
            <span class="carousel-control-next-icon"></span>
        </a>
    </div>
</div>
</body>
</html>

 
@model HelloWorldMvcApp.SampleViewModel
@{
    Layout = null;
}
​
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Bootstrap 4 Carousel</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js"></script>
<style>
.carousel{
    background: #2f4357;
    margin-top: 20px;
}
.carousel-item{
    text-align: center;
    min-height: 280px; /* Prevent carousel from being distorted if for some reason image doesn't load */

using System;
using System.Web.Mvc;
using System.Collections.Generic;

namespace HelloWorldMvcApp
{
	public class HomeController : Controller
	{
		[HttpGet]
		public ActionResult Index()
		{
			var model = new SampleViewModel();
			model.CarouselItemList = new List<CarouselItemModel>()
			{new CarouselItemModel()
			{ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+1", Alt = "ImageOne"}, new CarouselItemModel()
			{ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+2", Alt = "ImageOne"}, new CarouselItemModel()
			{ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+3", Alt = "ImageOne"}, new CarouselItemModel()};
			return View(model);
		}
	}
}

 
using System;
using System.Web.Mvc;
using System.Collections.Generic;
​
namespace HelloWorldMvcApp
{
    public class HomeController : Controller
    {
        [HttpGet]
        public ActionResult Index()
        {
            var model = new SampleViewModel();
            model.CarouselItemList = new List<CarouselItemModel>()
            {new CarouselItemModel()
            {ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+1", Alt = "ImageOne"}, new CarouselItemModel()
            {ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+2", Alt = "ImageOne"}, new CarouselItemModel()
            {ImagePath = "https://dummyimage.com/600x400/000000/0011ff&text=Slide+3", Alt = "ImageOne"}, new CarouselItemModel()};
            return View(model);
        }
    }
}

Json.NET version: Newtonsoft.Json, Version=9.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed
Initial JSON:
[
  {
    "MyStringArray": [
      "stringInput1",
      "stringInput2"
    ],
    "MyCharArray": [
      "a",
      "b",
      "c",
      "."
    ],
    "MyString": "dummy",
    "MyClass3Object": [
      {
        "MyString": "ListInput1",
        "MyRegex": {
          "Pattern": "[A-Z]",
          "Options": 0
        }
      },
      {
        "MyString": "ListInput2",
        "MyRegex": {
          "Pattern": "[0-9]",
          "Options": 0
        }
      }
    ]
  }
]
Deserialized and re-serialized JSON:
[
  {
    "MyStringArray": [
      "stringInput1",
      "stringInput2"
    ],
    "MyCharArray": [
      "a",
      "b",
      "c",
      "."
    ],
    "MyString": "dummy",
    "MyClass3Object": [
      {
        "MyString": "ListInput1",
        "MyRegex": {
          "Pattern": "[A-Z]",
          "Options": 0
        }
      },
      {
        "MyString": "ListInput2",
        "MyRegex": {
          "Pattern": "[0-9]",
          "Options": 0
        }
      }
    ]
  }
]
Initial and re-serialized are equivalent.