Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
( f ) to retain a copy , you must either have a printer connected to your personal computer or other device or , alternatively , the ability to save a copy through use of printing service or software such as adobe acrobat ® . 

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