)the efficiency for recursuvely calculating xn is
a. o(nlogn)
b. o(n)
c. o(logn)
d. o(n2)

(B) O(n).

Explanation:

When we recursively calculate xⁿ. We multiply x with itself  n times.in doing so we have to do this operation n times .So the time complexity will come out to be O(n).

for ex:

int product(int a ,int n)

{

   if(n==1)

   return a;

   return a*product(a,n-1);

}

This function will keep on doing these operation until it hit the base case it is doing the operation n times.