Question

the united states officially entered world war ii because of:
a. the japanese attack on pearl harbor.
b. japanese aggression in east asia.
c. the german armys siege of leningrad.
d. germanys invasion of the soviet union.

Explanation:

The U.S. had maintained neutrality in WWII until the surprise Japanese attack on the U.S. naval base at Pearl Harbor on December 7, 1941. The next day, the U.S. declared war on Japan, officially entering the conflict. The other options describe events that did not directly trigger U.S. entry into the war.

Answer:

A. the Japanese attack on Pearl Harbor.