How to increase the size of radio buttons on quiz slides

You have to create triggers to pass that information on to the interaction. What I prefer for this purpose is to start with a pick one interaction.  The purpose of making them a set is so that only one can be selected. If you want to submit multiple responses, they cannot be a set.

I've included some options in the attached sample that you may not need.  I have my own preference for unanswered questions and submit button.  They are found in slide 1. If you don't want them, use slide 2.

Don't change the order of any of the triggers, or they won't work right.