The Collapse of AT&T's Natural Monopoly in Long-Distance Telephone Service

The collapse of AT&T's natural monopoly in long-distance telephone service was caused by

A) Satellite technology that made it easier and less expensive for new companies to provide long-distance service.
B) The takeover of the telephone industry by the U.S. government.
C) Government regulation because of illegal collusion between AT&T and foreign competitors.
D) Inadequate profits.