C++ Pointers & Functions Interview Question:

What is the output of this program?

#include <iostream>
using namespace std;
void fun(int x, int y)
{
x = 20;
y = 10;
}
int main()
{
int x = 10;
fun(x, x);
cout << x;
return 0;
}
a) 10
b) 20
c) compile time error
d) none of the mentioned