Given the following algorithm for selection sort, which complexity class does this algorithm belong to?
Selection_sort(A)
for i = 1 to A.length
min = i
for j = i+1 to
A.length
if A[j] < A[min]
min =j
# end for
swap A[i], A[min]
# end for

a. O(n²)
b. O(1)
c. O(n!)
d. O(n)
e. O(lg n)