Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
portions of tripadvisor mobile software may use copyrighted material , the use of which tripadvisor acknowledges . 

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