If \(a\) and \(b\) are integers such that \(a > b > 1,\) which of the following cannot be a multiple of either \(a\) or

[Vincen]

If \(a\) and \(b\) are integers such that \(a > b > 1,\) which of the following cannot be a multiple of either \(a\) or \(b?\)

(A) \(a - 1\)
(B) \(b + 1\)
(C) \(b - 1\)
(D) \(a + b\)
(E) \(ab\)

Answer: C

Source: Manhattan GMAT