And let every other power know that this hemisphere intends to remain the master of its own house. which best describes the feeling kennedy intends to convey in this sentence?

a. openness and flexibility
b. dominance and unity
c. hostility and aggression
d. influence and vulnerability

This excerpt is mainly talking about how other powers want to be dominant- and the only way to do that is to rise over everyone else. Kennedy is saying that we will be in charge of ourselves and that we do not intend on having an authoritative power attempting to vanquish us.

In conclusion, your final answer should be B.

D. prior knowledge