Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
any personal data obtained from children and parents during contests will be kept until the contest ends and prizes are delivered , and then it will be deleted . 

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