Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
nonprofits , and not airbnb , are responsible for determining what , if any , portion of their listing fee is a charitable contribution and for providing guests charitable tax receipts for any applicable charitable contributions . 

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