Answer:
The following are the correct answers to each question:
Part A: Option b. One of Roosevelt's purposes for delivering the speech is to inform the American pople of Japan's attack on the US and other places in the Pacific. This is why the speech has an informative tone, as President Roosevelt gives various details and facts about the places Japan has attacked as well as the time the attacks happened.
Part B: Option A. Roosevelt uses repetition, employing the phe "last night" several times, to stress the number of coordinated attacks carried out by the Japanese. By stressing and repeting the phrase, the President reinforces the message that the actions taken by the Japanese were premeditated and organized in advance, while at the same time they were in negotiations with the American government.