Given an unsorted std::vector and a number n, what is the worst-case time complexity for finding the pair of integers whose sum is closest to n, using no additional memory? For example, given the vector(12, 3, 17, 5, 7} and n = 13, we would get the pair(5, 7).
A.Θ(log n)
B.Θ(n)
C.Θ(n log n)
D.Θ(n2)
E.0(29