You didn't list any of the possible outcomes, so I'll list all of the reasons the Han Dynasty DID fall.
If any of the answer choices include things I listed, it is not the correct answer and therefore through the process of elimination you should find the correct answers.
The Han Dynasty fell for these reasons:
- Internal Forces / Corruption
- Taxation within the Empire
- The Steppe Societies / The Huns
- Warlords and breaking into regions
- Disease
- Political Problems
- Inability to maintain the order of the public
- Lords wanted more land, the government gave, wanted more so killed neighbors
Hope this helps!
