Please select the tight time complexity of the following function in worst case.

sum(A, n)

{

flag = true

while(flag)

{

for i= 1 to (n/2)

for j = n down to i

if A[i] = A[j]

flag = false break

}

}

A. O(n)

B. O(n3)

C. O(n2)

D. O(n log n)