One of the Reasons for the Recent, Rapid Growth of Direct

One of the reasons for the recent, rapid growth of direct marketing in American society is the

A) fact that the United States has moved from an industrialized nation to a service nation.
B) increase in the number of hours individuals spend watching television.
C) nonproliferation of cellular phones.
D) increased use of consumer credit cards.
E) development of four-color printing presses.