using System;

public class Program

{

    public static void Main()

    {

        var t = new []{ typeof(DateTime?), typeof(DateTime) };

        var tt = new []{ typeof(DateTime?), typeof(DateTime) };

        foreach(var i in t)

        {

            foreach(var j in tt)

            {

                var res = i.IsAssignableTo(j);

                Console.WriteLine($"{i}.IsAssignableTo({j}) = {res}");

            }

        }

    }

}