Which of the following statement is correct about the C#.NET code snippet given below?

public class Sample
{
    public int x;
    public virtual void fun()
    { }
}
public class DerivedSample : Sample
{
    new public void fun()
    { }
}

1. A class
2. A property
3. A struct
4. A function
5. An interface

class Sample
{
    int i;
    Single j;
    double k;
    public Sample (int ii, Single jj, double kk)
    {
        i = ii;
        j = jj;
        k = kk;
    } 
}

namespace CuriousTabConsoleApplication
{ 
    class SampleProgram
    {
        static void Main(string[] args)
        { 
            int num = 1;
            funcv(num); 
            Console.Write(num + ", "); 
            funcr(ref num); 
            Console.Write(num + ", ");
        }
        static void funcv(int num)
        { 
            num = num + 10; Console.Write(num + ", ");
        }
        static void funcr (ref int num)
        { 
            num = num + 10; Console.Write(num + ", ");
        } 
    } 
}

1. true
2. false
3. new
4. ~
5. sizeof