I sell continuing education courses. I have an order form ([url removed, login to view]) which has multiple continuing education courses one can buy, and then the info is confirmed ([url removed, login to view]). On the order form, there are up to 3 checkboxes per course and all 3 can be clicked, however, I only want the purchaser to be able to click only 1 per course. In addition, there is a dropdown menu next to the checkboxes. If one clicks a checkbox (orders a course), I want to ensure that he also makes a selection in the dropdown menu. For my purposes, the design is appropriate for me, but if you think another design would be simpler and more appropriate, feel free to suggest so.