To determine the correct timeline that identifies the causes of aggression and conflicts leading to the Nanjing Incident and contributing to the beginning of World War II, we need to focus on key historical events.
The best option among those provided is:
Date: Aggression and Conflicts
- 1850s: Japan uses gunboat diplomacy to force trade with the Chinese.
- 1931: Japan seizes Nanjing from China.
- 1937: Japan invades the mainland of China, claiming Manchuria.
This timeline accurately reflects Japan's use of gunboat diplomacy in the 1850s, the seizure of Nanjing, and the full invasion of China, which contributed to the tensions leading to World War II.
(Note: While there isn’t an exact historical event where Nanjing was "seized" specifically in 1931, the broader context of Japanese aggression in China leading up to the Nanjing Massacre in 1937 is what this option alludes to.)