How were the japanese able to surprise the us at pearl harbor?

The correct answer is D) Japanese aircraft carriers had approached Hawaii unnoticed.

The other options of the question were A) Japanese land forces had invaded Hawaii unnoticed. B) Japanese submarines invaded Pearl Harbor unnoticed. C) Japanese airplanes had flown to the US mainland unnoticed

The Japanese were able to surprise the US at Pearl Harbor because "Japanese aircraft carriers had approached Hawaii unnoticed."

We are talking about the Pearl Harbor attack of December 7, 1941, during World War II. The United States had maintained its distance from the European conflict due to the policy of neutrality installed by US President Woodrow Wilson. However, after the attack, President Wilson asked Congress for a declaration of war and that is how the United States entered World War II.  

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