Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
( c ) our `` monthly '' subscription is paid in monthly installments . 

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