Answer:
B). To further develop the sense of betrayal.
Step-by-step explanation:
The 'Infamy Speech' was delivered on the 8th of December 1941 right after Japan's thrust on the naval base of the United States located at Pearl Harbor in Hawaii and its open declaration of war. In this speech, Roosevelt primarily aimed to show Japan's betrayal and America being an innocent victim of this. He asserts that all their efforts to reach a peaceful solution remained unsuccessful.
As per the question, the president employs the 'list of additional attacks' with a key purpose to 'develop the sense of betrayal' by Japan among the United States people and asked for their support in this war. The list of attacks(Last night, Japanese forces attacked HongKong...Guam...Wake Island...Midway Island, etc.) allow him to portray reveal the 'dastardly' nature of Japan and present America as the passive victim of aggression of Japan which allowed him to gain audience's faith and support in this war. Thus, option B is the correct answer.