The correct answer is B. Germany invaded Poland. This event sparked the beginning of World War II. To come to this conclusion, you can recall the historical context and knowledge about the start of the war. In 1939, Germany launched a military invasion of Poland, which violated international treaties and agreements. Britain and France, as allies of Poland, had previously made it clear that aggression against Poland would result in their declaration of war on Germany. Therefore, the invasion of Poland provoked Britain and France to officially declare war on Germany.
