Question 24 - Quantitative Practice Test for the GMAT

Which of the following must be a multiple of \(8\), if \(x\) and \(y\) are factors of \(8\), both are greater than \(1\), and \(x\) and \(y\) are not both \(2\).

I) \((x+y)^2\)

II) \(xy + 4y\)

III) \(3(y-x)\)