Which Statement Best Illustrates Complementary Goods

Which statement best illustrates complementary goods?

A) The price of tennis rackets declines so your economics instructor decides to take tennis lessons and purchases several cans of new tennis balls.
B) The price of Apple Macintosh computers declines so your economics instructor sells his or her IBM personal computer and buys a Macintosh.
C) After receiving a promotion and a hefty year-end bonus from the college, your economics instructor decides to stop buying denim jeans and switches to clothing befitting his or her loftier position on the faculty.
D) Fearing that the price of pipe tobacco will rise next year, your economics professor goes to his local tobacconist and purchases an ample supply to last for several years.