Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
opt-out of agreement to arbitrate : you can decline this agreement to arbitrate by contacting legal@fitbit.com within 30 days of first accepting these terms of service and stating that you ( include your first and last name ) decline this arbitration agreement . 

```
. OPTIONS: ["Contract by using", "Unilateral termination", "Unilateral change", "None", "Arbitration", "Content removal", "Limitation of liability", "Jurisdiction", "Choice of law"].