What will be the output of the following C++ code?

#include <stdio.h> 
#include<iostream>
using namespace std;
int main()
{
    int a = 21;
    int c ;
    c = a++;
    cout << c;  
    return 0;
}

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