Define a b=a^{2} b-a b^{2}. Which of the following describes the set of points (x, y) for which x y=y ?

**Answer Choices**

A. a finite set of points

B. one line

C. two parallel lines

D. two intersecting lines

E. three lines

Define a b=a^{2} b-a b^{2}. Which of the following describes the set of points (x, y) for which x y=y ?

**Answer Choices**

A. a finite set of points

B. one line

C. two parallel lines

D. two intersecting lines

E. three lines