What was the primary result of the Japanese attack on Pearl Harbor?

The primary result of the Japanese attack on Pearl Harbor was that it prompted the United States to enter World War II. This surprise military strike took place on December 7, 1941, and resulted in significant losses for the U.S. Pacific Fleet, including the destruction or damage of numerous battleships and aircraft. Prior to the attack, the United States had maintained a position of neutrality in the conflict. The attack galvanized public sentiment and united the American populace in support of entering the war.

Following the attack, President Franklin D. Roosevelt delivered his famous "Day of Infamy" speech, which led Congress to declare war on Japan, marking the official entry of the United States into World War II. This event significantly shifted the dynamics of the war, as the United States would go on to play a crucial role in both the Pacific and European theaters.

While the other options may touch on consequences of the attack, they do not capture the fundamental impact of the event as clearly as the United States' entry into the war, which fundamentally altered the course of the conflict on a global scale.