Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
we will notify you before we make material changes to these terms and give you an opportunity to review the revised terms before continuing to use the fitbit service . 

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