Part A:
Answer
One of Roosevelt's purposes was to inform the American people of Japan's attack on the US and other places in the Pacific.
The other possible answer is the one that mentions Japan being an ally of the Nazis, however the word "Nazi" is never mentioned on the speech.
Part B:
Answer
He uses repetition, employing the word ¨attack¨ over and over, to inspire Americans to join the armed forces and aggressively take on the enemy.
This is definitely the rhetoric that applies to advance his purpose from part A. The other options wouldn't apply.