<span>c. The United States entered World War II because Japan attacked its navy.
Not only had Japan attacked the US naval base at Pearl Harbor, but that was an attack against American home soil, in the US territory of Hawaii. (Hawaii later became a state, in 1959.) The next day, President Roosevelt went before Congress and described December 7, 1941 as "a date that will live in infamy" because of the Japanese attack. Congress declared war against Japan, drawing the USA into World War II. Germany and Italy, allied with Japan, responded with a declaration of war against the USA, and the USA responded by declaring war against Germany and Italy as well.
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