Which of the following statements are correct about the C#.NET code snippet given below?

namespace CuriousTabConsoleApplication
{ 
    class Sample
    { 
        int i, j; 
        public void SetData(int ii, int jj)
        {
            this.i = ii;
            this.j = jj 
        } 
    } 
    class MyProgram
    { 
        static void Main(string[ ] args)
        { 
            Sample s1 = new Sample(); 
            s1.SetData(10, 2); 
            Sample s2 = new Sample(); 
            s2.SetData(5, 10); 
        } 
    } 
}

namespace CuriousTabConsoleApplication
{ 
    class Sample
    { 
        public int func()
        {
            return 1;
        } 
        public Single func()
        { 
            return 2.4f ;
        } 
    } 
    class Program
    { 
        static void Main(string[ ] args)
        {
            Sample s1 = new Sample(); 
            int i;
            i = s1.func(); 
            Single j; 
            j = s1.func(); 
        } 
    } 
}

namespace CuriousTabConsoleApplication
{
    class SampleProgram
    {
        static void Main(string[ ] args)
        {
            int i, j;
            int[ , ] arr = new int[ 2, 2 ];
            for(i = 0; i < 2; ++i)
            {
                for(j = 0; j < 2; ++j)
                {
                    arr[i, j] = i * 17 + i * 17;
                    Console.Write(arr[ i, j ] + " ");
                }
            }
        }
    }
}

int i = 0; 
do
{
    Console.WriteLine(i);
    i+ = 1; 
} while (i <= 10);

int i = 0; 
do
{
    Console.WriteLine(i);
} until (i <= 10);

int i;
for (i = 0; i <= 10 ; i++)
    Console.WriteLine(i);

int i = 0; 
while (i <= 11)
{
    Console.WriteLine(i);
    i += 1; 
}

int i = 0;
do while ( i <= 10)
{
    Console.WriteLine(i); 
    i += 1;
}

int i = 0;
do until (i <= 10)
{
    Console.WriteLine(i);
    i+=1; 
}

int i = 1, j = 1, val;
while (i < 25)
{
    Console.Write(j + " ");
    val = i + j;
    j = i;
    i = val;
}

1. A function cannot be called from a subroutine.
2. The ref keyword causes arguments to be passed by reference.
3. While using ref keyword any changes made to the parameter in the method will be reflected in that variable when control passes back to the calling method.
4. A subroutine cannot be called from a function.
5. Functions and subroutines can be called recursively.

decimal static fun(int i, Single j, double k)
{ ... }

decimal fun(int i, Single j, double k)
{ ... }

static decimal fun(int i, Single j, double k)
{ ... }

static decimal fun(int i, Single j, double k) decimal
{ ... }

static fun(int i, Single j, double k)
{ 
    ... 
    return decimal;
}

class Sample
{
    public void MyFun(int i, Single j)
    {
        Console.WriteLine("Welcome to CuriousTab !");
    }
}

delegate void del(int i);
Sample s = new Sample();
del d = new del(ref s.MyFun);
d(10, 1.1f);

delegate void del(int i, Single j);
del d;
Sample s = new Sample();
d = new del(ref s.MyFun);
d(10, 1.1f);

Sample s = new Sample();
delegate void d = new del(ref MyFun);
d(10, 1.1f);

delegate void del(int i, Single]);
Sample s = new Sample();
del = new delegate(ref MyFun);
del(10, 1.1f);