Hi Peter,
I took a look at your file, and I think you've stumbled upon a common problem. :) In your set up, for the question to be marked "incorrect" your trigger is checking that ALL the elements are not equal to the expected setting - when in reality, all you need is one item to not match the expected value. So instead of using the "AND" condition you'll want to utilize the "OR" condition.
Once you do that, if the user doesnt' answer one element correctly the "wrong" item off stage will still be "selected" and therefore the question counts as being answered. As you have it set right now - nothing is selected unless they match all those conditions.
Hope that helps!