Which of the following statements are correct about the String Class in C#.NET? 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 Mu

Which of the following statements are correct about the String Class in C#.NET?

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;