None of these answers are correct. It started when Prime Minister Chamberlain and the rest of the European allies refused to put Hitler in check well before the official recognized date of the German invasion of Poland of September 1, 1939. As a result, what should have been an European affair turned into World War II. Peace through strength not indecision.
WW2 started by the invasion in Poland on sept 1 1939.
But this one is not a bad one anyway, maybe Bush doesn't knows anymore, the same as he forgott to join the army to fight there once.
GWBush may know the answer, but he surely can't interpret some important details of the event. If he could, he would compare his war to the fascist Axis powers instead of to the Allied powers.
Here is my hint: Don't be fooled by Answer b. That may be the event that brought the United States into the war, but the war itself started way before that. Remeber the German occupation of Poland and the Japanese invasion of Nanking happened before December 7 1941.