What are the key facts of december 7, 1941 (pearl harbor)?

December 7, 1941 (or 6, 1941, depending on which time zone you were in), was the day of the Battle of Pearl Harbor, in which Japan broke political ties with the US, and attacked the US harbors in Pearl Harbor, destroying multiple infrastructure and battleships before the US had time to react. This battle also sparked the US to declare war on Japan, and led to the internment of Japanese American Nisei and Issei in an attempt to rid the US of spies & political enemies.

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yup! you are correct it is b.