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