Talking with one teacher (Antonio Vicent) he pointed me about the interesting possibility of enable the possibility to delete choice answers by the teacher.

This would allow teachers to perform periodic choices about the same question to detect changes in student preferences and so on.

As I see the feature I can see two different paths to add this functionality:

1.- Simple: Add a new Delete answers button /link that, after verification will delete all the answers.

2.- Complex: Store previous answers to other table (or the same with some type of saved version field to allow new choices to be performed by students. Create some reports to analyze changes over different versions.

Just one idea but I think it could be a good idea (from teacher perspective).