using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string s = @"

            {

              ""id"": 347745,

              ""results"": [

                {

                  ""iso_3166_1"": ""US"",

                  ""release_dates"": [

                    {

                      ""certification"": ""R"",

                      ""iso_639_1"": """",

                      ""note"": """",

                      ""release_date"": ""1936-12-12T00:00:00Z"",

                      ""type"": 3

                    }

                  ]

                }

              ]

            }";

​

        var obj = JsonConvert.DeserializeObject<JObject>(s);

        var _currentMPAARating = (string)obj.SelectToken("..certification");

        Console.WriteLine(_currentMPAARating);

    }

}