Answer Happy

What is the output of the program?#include <iostream>#include <string>using namespace std;int main(){string s1="Wo";string s2;s2 = s1;string s3;s3 = s2.append("rldHello");cout << s3;return( 0 );}

A. It prints: WorldHello
B. It prints: HelloWo
C. It prints: World
D. It prints: Hello