The correct timeline that identifies the cause of aggression and conflicts that led to the Nanjing Massacre in China and contributed to the beginning of World War II is:
Date: Aggression and Conflicts
- 1850s: Japan uses gunboat diplomacy to force trade with the Chinese.
- 1931: Japan seizes Manchuria from China.
- 1937: Japan invades the mainland of China, claiming Beijing and Shanghai.
This timeline accurately reflects Japan's aggressive actions in Asia leading up to the events in Nanjing and the larger context of World War II.