Finish the following sentence with the best choice: To unlock Knuckles in Sonic Adventure.

Choices:
- Reach the part where you fight E-102 (as Sonic or Tails), fight him and Chaos 6.
- Reach the part where you fight Knuckles (as Sonic or Tails), fight him and Chaos 4.

Answer:
Reach the part where you fight Knuckles (as Sonic or Tails), fight him and Chaos 4.