A. The United States entered the war on the side of the Allies.
Explanation:
On December 7, 1941
, Pearl Harbor was attacked by Japanese forces, this lead to thousands of casualties among Americans. This attack was very shocking for America, as they tried to avoid the war, and did not want to fight in it. The attack on Pearl Harbor was not forgotten and the next day, on December 8th, 1941, the United States had declared war on Japan. The United States joined the Allies, which made them the last to join the Allies during World War II.
