How many service branches comprise the Defense Department?

Which of the following instances is an example of deterrence?

a. A state develops a series of fortifications that make it impractical for neighbors to invade it. b. A state establishes a second-strike bomber fleet capable of destroying its neighbor's industrial infrastructure. c. A state establishes a first-strike bomber fleet that results in its neighbor doing the same. d. A state launches a pre-emptive strike against a neighbor that was mobilizing to invade it. e. A state launches a retaliatory strike against a neighbor that has invaded its territory.

Advocates of limited nuclear proliferation believe that

a. even small nations can build an adequate deterrent. b. nuclear deterrence requires only a few nuclear weapons. c. nuclear deterrence is difficult to achieve. d. we should not worry about a nuclear Iran.