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

#include<iostream>
using namespace std;
int main ()
{
   int cin;
   cin >> cin;
   cout << "cin: " << cin;
   return 0;
}

A. .cpp B. .cc C. .cxx D. .c

A. char B. float C. boolean D. double

A. File output stream B. File input stream C. Standard output stream D. Standard input stream

A. struct B. interface C. class D. object