Answer:
B. Germany invaded Poland, bringing Great Britain, France, and the United States into the war.
Step-by-step explanation:
Option B seems to be correcct at first sight because the invasion to Poland was the trigger to lead the Allies to war, however the United States went into war in Dcember 1941 after the attack at Pearl Harbor on December 7. To sum up, it is false that the invasion to Poland was the cause to bring Great Britain, France and the United States into war prior to December 1941 because United States only brought into war during December 1941.