What is the output of the following C++ code?

#include <iostream>
using namespace std;
int fun(int n)
{
    if (n == 0)
        return 0;
    return n + fun(n - 1);
}
int main()
{
    cout << fun(4);
    return 0;
}
                        

Options

• A. 4
• B. 6
• C. 10
• D. More than one of the above
• E. None of the above