When Dwight Eisenhower sent federal troops into Central High School in Little Rock,
Arkansas,in 1957,it demonstrated that the

A) president may make unilateral use of the emergency powers to protect states against domestic disorder.
B) president requires the federal court's approval before using troops in domestic disturbances.
C) use of the president's emergency powers against domestic disorder necessitates a request by the governor of the state in question.
D) president needs congressional authorization to use troops in both domestic and international situations.