If s1 and s2 are references to two strings, then which of the following is the correct way to compare the two references?

1. String s = "123"; 
   int i;
   i = (int)s;

2. String s = "123";
   int i;
   i = int.Parse(s);

3. String s = "123"; 
   int i;
   i = Int32.Parse(s);

4. String s = "123"; 
   int i;
   i = Convert.ToInt32(s);

5. String s = "123"; 
   int i;
   i = CInt(s);

String s1 = "Nagpur";
String s2;
s2 = s1.Insert(6, "Mumbai"); 
Console.WriteLine(s2);

String s1, s2; 
s1 = "Hi"; 
s2 = "Hi";

1. String objects cannot be created without using new.
2. Only one object will get created.
3. s1 and s2 both will refer to the same object.
4. Two objects will get created, one pointed to by s1 and another pointed to by s2.
5. s1 and s2 are references to the same object.

String s1 = "Five Star";
String s2 = "FIVE STAR";
int c;
c = s1.CompareTo(s2);
Console.WriteLine(c);

namespace CuriousTabConsoleApplication
{ 
    class Baseclass
    { 
        public void fun()
        { 
            Console.WriteLine("Hi" + " ");
        } 
        public void fun(int i)
        {
            Console.Write("Hello" + " ");
        } 
    } 
    class Derived: Baseclass
    {
        public void fun()
        {
            Console.Write("Bye" + " ");
        } 
    } 
    class MyProgram
    { 
        static void Main(string[ ] args)
        { 
            Derived d; 
            d = new Derived(); 
            d.fun(); 
            d.fun(77);
        } 
    } 
}

1. Two strings can be concatenated by using an expression of the form s3 = s1 + s2;
2. String is a primitive in C#.NET.
3. A string built using StringBuilder Class is Mutable.
4. A string built using String Class is Immutable.
5. Two strings can be concatenated by using an expression of the form s3 = s1&s2;

1. if(s1 = s2)

2. if(s1 == s2)

3. int c;
   c = s1.CompareTo(s2);

4. if( strcmp(s1, s2) )

5. if (s1 is s2)

String s1 = "String";
String s2; 
s2 = s1;

String s1 = "String" ; 
String s2;
s2 = String.Concat(s1, s2);

String s1 = "String"; 
String s2;
s2 = String.Copy(s1);

String s1 = "String"; 
String s2;
s2 = s1.Replace();

String s1 = "String"; 
String s2;
s2 = s2.StringCopy(s1);