Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
this limited right may be revoked at any time in fitbit 's sole discretion . 

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