Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
in proving the service of any notice via email , it will be sufficient to prove that such e-mail was sent to the specified e-mail address of the addressee . 

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