Answer:
C. ?????
Explanation:
Given code:
void unknown(int n)
{
if(n>0)
unkown(n-1);
System.out.print("?");
}
Calling code: unknown(4)
This is a recursive invocation of unknown function and causes ? to be printed 5 times once each for following values of n.
When n becomes 0, termination condition is reached and the function returns.
So the output is ?????