Which of the Following Is the Best Example of a Vertically

Which of the following is the best example of a vertically integrated firm?

A) General Electric, which produces light bulbs, jet engines, washing machines, and so on
B) Kinko's, which has a photocopy store near many colleges and universities
C) Americam Apparel, which from a single building in downtowm LA, controls the dyeing, finishing, designing, sewing, cutting, marketing and distribution of the company's product.
D) Intel, which makes computer chips for most of the computer manufacturers
E) Century 21, which has real estate offices that help people sell a house in one city and buy another house in another city