At this moment you have to click the answers to see if you can select more then one or we need to put 'more answers possible' in the question. 

Improvement:

Small circles in front of the answers for the questions where there is only one answer possible.

Small squares/checkboxes if there are more answers possible. 

So it will be easier to see what you're options are as a customer by just looking at it.

See the attachments for examples of the icons/symbols.