If ab > cd and a, b, c and d are all greater than zero, which of the following CANNOT be true?

What would be an alternative way to answer this question ?

Thanks

Please post the complete text of the question, including answers. I can't figure out what is and isn't true if I can't see the answers I'm supposed to be evaluating... :)

Apologies Stacy ... here's the question in FULL:

If ab > cd and a, b, c and d are all greater than zero, which of the following CANNOT be true?

(A) c > d
(B) d > a
(C) b/c < d/a
(D) a/c > d/b
(E) (cd)^2 < (ab)^2

The solution in the Question bank suggests going through each answer choice and plugging-in numbers.
But I am keen to find out if there is another approach to tackle this type of question ?

Thanks in advance.

You can reason your way through this one without plugging in numbers:

A - Given ab > cd, on the right side of the inequality, one of three things can be happening: c > d, c = d, or c < d.
B - Similar to A, but about the left side.
C - If you divide both sides by c and by a, you get b/c > d/a. The inequality sign is facing the other way. C is not possible.
D - Here, divide both sides by c and by b and you get a/c > d/b.
E - Square both sides of the inequailty ab > cd and you wind up with the expression in answer choice E.

Rey