Which of the Following Was NOT a Cause of the Second

Which of the following was NOT a cause of the Second World War's expansion from a European war to a genuinely global conflict?

A) The eruption of conflict between Axis and Allied forces in French and German colonies in Africa.
B) Germany's submarine campaign to starve out Great Britain.
C) Japan's surprise attack on the Allies in the Pacific and its stunning early success.
D) The fighting in North Africa,which threatened the Suez Canal and Allied access to Middle Eastern oil.
E) The establishment of an alliance between Nazi Germany and the Empire of Japan.