php mcq questions with answers

If two StringBuilder objects contain the same string then
A. they represent the same memory location
B. the are two different objects
C. if one changes, so will the other
D. None of the above
The proper way to convert a string to all lowercase is________.
A. String = string.ToLower(string);
B. ToLower(string);
C. string.ToLower();
D. string.ToLower(string);