using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var props = new Dictionary<string, object>();

        var json = "[{\"name\":\"source\",\"choices\":[\"Email\",\"Portal\",\"Phone\",\"Forum\"]}]";

        var obj = Newtonsoft.Json.JsonConvert.DeserializeObject<List<TestClass>>(json);

        Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(obj));

    }

    public class TestClass

    {

        [Newtonsoft.Json.JsonProperty("name"), System.Text.Json.Serialization.JsonPropertyName("name")]

        public string Name { get; set; }

​

        [Newtonsoft.Json.JsonProperty("choices"), System.Text.Json.Serialization.JsonPropertyName("choices")]

        public object Choices { get; set; }

    }

}