Which of the following statements are correct about an enum used inC#.NET?

1. To use the keyword enum, we should either use [enum] or System.Enum.
2. enum is a keyword.
3. Enum is class declared in System.Type namespace.
4. Enum is a class declared in the current project's root namespace.
5. Enum is a class declared in System namespace.

namespace CuriousTabConsoleApplication
{ 
    class SampleProgram
    { 
        static void Main(string[] args)
        { 
            int[]arr = newint[]{ 1, 2, 3, 4, 5 }; 
            fun(ref arr);
        }
        static void fun(ref int[] a)
        { 
            for (int i = 0; i < a.Length; i++)
            { 
                a[i] = a[i] * 5; 
                Console.Write(a[ i ] + " "); 
            } 
        } 
    } 
}

struct Emp
{
    public String name;
    public int age;
    public Single sal; 
}
Emp e = new Emp();

e.name = "Amol"; 
e.age = 25; 
e.sal = 5500;

With e
{
    .name = "Amol";
    .age = 25;
    .sal = 5500; 
}

With emp e
{
    .name = "Amol";
    .age = 25;
    .sal = 5500; 
}

e -> name = "Amol"; 
e -> age = 25;
e -> sal = 5500;

name = "Amol"; 
age = 25;
sal = 5500;

int[ , ] intMyArr = {{7, 1, 3}, {2, 9, 6}};

1. intMyArr represents rectangular array of 2 rows and 3 columns.
2. intMyArr.GetUpperBound(1) will yield 2.
3. intMyArr.Length will yield 24.
4. intMyArr represents 1-D array of 5 integers.
5. intMyArr.GetUpperBound(0) will yield 2.

namespace CuriousTabConsoleApplication
{ 
    class Sample
    { 
        int i; 
        Single j; 
        public void SetData(int i, Single j)
        { 
            this.i = i; 
            this.j = j;
        }
        public void Display()
        { 
            Console.WriteLine(i + " " + j);
        } 
    } 
    class MyProgram
    { 
        static void Main(string[ ] args)
        {
            Sample s1 = new Sample(); 
            s1.SetData(36, 5.4f); 
            s1.Display(); 
        } 
    } 
}

1. If we do not return a value from a subroutine then a value -1 gets returned.
2. Subroutine definitions cannot be nested.
3. Subroutine can be called recursively.
4. To return the control from middle of a subroutine exit subroutine should be used.
5. Subroutine calls can be nested.