The National Defense of the United States Is Not Rival

Multiple Choice

The national defense of the United States is not rival because

A) my enjoyment of the national defense does not diminish your enjoyment of the national defense of the United States.
B) my enjoyment of the national defense does diminish your enjoyment of the national defense of the United States.
C) once the nation is defended, it is impossible to prevent any single person from enjoying the benefit of this defense.
D) once the nation is defended, it is possible to prevent any single person from enjoying the benefit of this defense.