Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
we may modify or discontinue virtual items or in-game currency at any time . 

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