For the code snippet shown below, which of the following statements are valid?

public class Generic<T>
{
    public T Field; 
    public void TestSub()
    {
        T i = Field + 1;
    }
}
class MyProgram
{
    static void Main(string[] args)
    {
        Generic<int> gen = new Generic<int>();
        gen.TestSub();
    }
}

public class TestCuriousTab
{
    public void TestSub<M> (M arg)
    {
        Console.Write(arg);
    }
}
class MyProgram
{
    static void Main(string[] args)
    {
        TestCuriousTab tab = new TestCuriousTab();
        tab.TestSub("CuriousTab ");
        tab.TestSub(4.2f);
    }
}

1. Stack
2. Tree
3. SortedDictionary
4. SortedArray

1. Generics is a language feature.
2. We can create a generic class, however, we cannot create a generic interface in C#.NET.
3. Generics delegates are not allowed in C#.NET.
4. Generics are useful in collection classes in .NET framework.
5. None of the above

public class Generic<T>
{
    public T Field;
}
class Program
{
    static void Main(string[ ] args)
    {
        Generic<String> g = new Generic<String>();
        g.Field = "Hello";
        Console.WriteLine(g.Field);
    }
}

public class MyContainer<T> where T: IComparabte
{
    // Insert code here
}

1. Class MyContainer requires that it's type argument must implement IComparabte interface.
2. Type argument of class MyContainer must be IComparabte.
3. Compiler will report an error for this block of code.
4. This requirement on type argument is called as constraint.