The time complexity of the following C function is (assume n > Q):
int recursive (int n) {
if (n == 1)
return (1);
else
return (recursive (n -1) + recursive (n -1));
}

A

$$O(n)$$

B

$$O(n \log n)$$

C

$$O(n^{2})$$

D

$$O(2^{n})$$