For all numbers \(a\) and \(b,\) the operation \(@\) is defined by \(a@b = a^2 - ab.\) If \(xy \ne 0,\) then which of

For all numbers \(a\) and \(b,\) the operation \(@\) is defined by \(a@b = a^2 - ab.\) If \(xy \ne 0,\) then which of the following can be equal to zero?

I. \(x@y\)

II. \((xy)@y\)

III. \(x@(x + y)\)

A. II only
B. I and II only
C. I and III only
D. II and III only
E. All of the above

Answer: B

Source: Magoosh