C Programming Syntax Error: Correcting Code for Fibonacci Sequence Calculation

There is a syntax error in the code. The return statement in the function is missing a closing parenthesis. It should be:

'return (fun(n-1) + fun(n-2));'

Also, the main function is missing opening and closing braces. It should be:

'int main(void) { printf('%ld\n', fun(6)); return 0; }'

With these corrections, the output of the program is:

12

Therefore, the answer is C) 12.