1. Which event triggered the United States' entry into World War II in December 1941? A. The bombing of Pearl Harbor by Japan B. The invasion of Poland by Germany C. The attack on the USS Maine in Havana Harbor D. The sinking of the Lusitania by a German submarine Answer: A. The bombing of Pearl Harbor by Japan Rationale: The attack on Pearl Harbor on December 7, 1941, led to the United States officially entering World War II as a result of Japan's surprise military strike on the U.S. naval base in Hawaii. 2. Which military leader was in charge of the Allied forces in Europe during World War II? A. General Douglas MacArthur B. General Dwight D. Eisenhower C. General George S. Patton D. General Omar Bradley Answer: B. General Dwight D. Eisenhower Rationale: General Dwight D. Eisenhower was appointed Supreme Commander of the Allied Expeditionary Force in Europe during World War II and played a crucial role in the planning and execution of the D-Day invasion.