Cpp Programming 71 – Which of the following cannot be friend?

#include
int main()
{
int arr[] = {1, 2 ,3, 4, 5};
int &zarr = arr;
for(int i = 0; i <= 4; i++) { arr[i] += arr[i]; } for(i = 0; i <= 4; i++) cout<< zarr[i]; return 0; }

[A].The program will print the output 1 2 3 4 5.
[B].The program will print the output 2 4 6 8 10.
[C].The program will print the output 1 1 1 1 1.
[D].It will result in a compile time error. 

Answer: Option D