Answer:
D. Japan carried out an explosion of one of its own trains in Chinese Manchuria.
The Manchurian Incident, also known as the Mukden Incident, occurred on September 18, 1931, when a section of the South Manchuria Railway owned by Japan was dynamited near Shenyang (Mukden), in the Chinese province of Manchuria. The explosion was blamed on Chinese dissidents and used as a pretext for the Japanese to invade and occupy Manchuria, leading to the establishment of the puppet state of Manchukuo.