Question

Which is President Kennedy’s intent when using questions in the last paragraph of this excerpt?

Answer 1

If you look at the questions, you can see that they do not actually demand an answer: they are rhetorical questions. Namely, he wants the listeners to ask themselves the questions, and answer with a "yes" - he wants them to thing about whether they will join and he wants them to say "yes" - so the answer is that he wants to motivate the listeners - the answer is A)