What will be the time complexity of the following code?

#include<stdio.h> 
int power(int x, int y) 
{ 
    int temp; 
    if( y == 0) 
        return 1; 
    temp = power(x, y/2); 
    if (y%2 == 0) 
        return temp*temp; 
    else
        return x*temp*temp; 
} 
int main() 
{ 
	int x = 2; 
    int y = 3; 
 
	printf("%d", power(x, y)); 
	return 0; 
}

A. O(1)

B. O(n)

C. O(log n)

D. O(n log n)

Answer: Option C