Which is the correct way of concatenating a character at the end of a string object?

way 1:
string s;
s = s + 'a';
 
way 2:
string s;
s.push_back('a');

A. A collection of functions B. A reserved keyword in C++ C. A blueprint for creating objects D. A way to declare arrays of data

A. new B. create C. object D. None of the above

A. A reserved keyword in C++ B. An instance of a class C. A way to declare arrays of data D. None of the above

A. To hide the implementation details of a class B. To create multiple instances of a class C. To initialize the object's data members D. To destroy the object