Final answer:
The effect of the bombing of Pearl Harbor was that it led to the D. United States officially entering World War II after President Franklin D. Roosevelt requested Congress to declare war on Japan.
Step-by-step explanation:
The bombing of Pearl Harbor had a significant impact, leading to a pivotal turn in World War II. The effect of the bombing was that the United States officially entered World War II. On December 7, 1941, Japan launched a surprise attack on the U.S. naval base at Pearl Harbor, causing massive casualties and damage. This event led President Franklin D. Roosevelt to request Congress to declare war on Japan, effectively abandoning the nation's prior isolationist policy and signaling the U.S. to become a major participant in the war against the Axis powers. Consequently, America also began aiding its allies in various other capacities, becoming the 'arsenal of democracy' and rallying its resources for the war effort.