a, b, c, and d are positive integers where a is a factor of b and c is a factor of d. Which of the following is NOT necessarily an integer?\nOptions:\n(A) (ac) /(bd) \n(B) (bd) /(ac) \n(C) (bcd) /a\n(D) d/c + b/a\n(E) (a + b) d/c
Let's be accurate as possible. Think before you answer.
(A)
As per the question, let a = 2, b = 6, c = 5, and d = 10.

Plugging these into the answer choices, only A does not yield an integer.

.

Therefore, the answer is (A)