单选题：Let n be a non-negative integer representing the size of input.

Let $$n$$ be a non-negative integer representing the size of input. The time complexity of the following piece of code is:

void func(int n) {
int i = 1;

while(i <= n)
i = i*2;
}




A.$$O(n) $$
B.$$O(n^2) $$
C.$$O(\log_2n) $$
D.$$O(n^{1/2}) $$


答案：C