The correct answer is B. A U.S. naval base in Hawaii
Step-by-step explanation:
On December 7 of 1941, the Japanese military forces attacked a naval base that was located at Pearl Harbor, Hawaii which was known as the Attack on Pearl Harbor. This attack had an important effect on the position of U.S. government in relation to World War II as until the attack the U.S. was a neutral country, but due to this the government decided to declare war on Japan one day after the attack which implied the U.S. began to be part of the war especially after Germany and Italy that supported Japan decided to declare war on the U.S. Therefore, the U.S. declared war on Japan in 1941 because of an attack on a U.S. naval base in Hawaii.