Which of the following is the correct way to define a variable of the type struct Emp declared below?

struct Emp
{
    private String name; 
    private int age; 
    private Single sal;
}

1. Emp e(); e = new Emp();
2. Emp e = new Emp;
3. Emp e; e = new Emp;
4. Emp e = new Emp();
5. Emp e;

namespace CuriousTabConsoleApplication
{ 
    struct Sample
    {
        public int i;
    }
    class MyProgram
    { 
        static void Main(string[] args)
        {
            Sample x = new Sample();
            Sample y;
            x.i = 9;
            y = x;
            y.i = 5;
            Console.WriteLine(x.i + " " + y.i); 
        } 
    } 
}

namespace CuriousTabConsoleApplication
{ 
    struct Sample
    {
        public int i;
    }
    class MyProgram
    { 
        static void Main()
        {
            Sample x = new Sample(); 
            x.i = 10; 
            fun(x); 
            Console.Write(x.i + " ");
        }
        static void fun(Sample y)
        {
            y.i = 20; 
            Console.Write(y.i + " ");
        } 
    } 
}

namespace CuriousTabConsoleApplication
{ 
    struct Sample
    { 
        public int i;
    }
    class MyProgram
    { 
        static void Main(string[] args)
        {
            Sample x = new Sample(); 
            x.i = 10; 
            fun(ref x); 
            Console.Write(x.i + " ");
        }
        public static void fun(ref Sample y)
        { 
            y.i = 20;
            Console.Write(y.i + " "); 
        } 
    } 
}

class Trial
{ 
    int i;
    Decimal d;
}
struct Sample
{
    private int x;
    private Single y;
    private Trial z;
}
Sample ss = new Sample();

struct Book
{
    private String name; 
    private int noofpages; 
    private Single price;
}
Book b = new Book();

1. A Structure can be declared within a procedure.
2. Structs can implement an interface but they cannot inherit from another struct.
3. struct members cannot be declared as protected.
4. A Structure can be empty.
5. It is an error to initialize an instance field in a struct.