Multiple choice matrix/grid

To ensure that only one button within each row can be selected, you can group the buttons into a buttonset (one for each row). Here is some info on button sets.

For the Correct/Incorrect feedback, you could use the state of a button in a trigger. Change the state of object Row1Feedback to Correct, if Row1TrueButton is Selected else Change the state of object Row1Feedback to Incorrect.

Or (as you already figured out), set up a variable for each row, the variable's value is changed every time a radio button in the row is clicked. Then based on the variable value, show the feedback.

In essence, each row is a multiple-choice question. However, because there are multiple rows, what you need is a multiple-response question. 

It's possible to rework a standard multiple-response question, but I think it'd be easier to design it as a Freeform Pick Many. 

You'll need to put the buttons in each row into a button set, so that only one can be selected at a time. 

If you want to ensure the user selects something in each row, you'll need to track those selections with variables. 

Here are resources that might be helpful:

• Converting slides to Freeform interactions
• Working with Button Sets
• Ranking Order Interaction 
• The Value of Variables
• Tracking Responses to Custom Questions or Surveys
• Limiting How Many Selections a User Can Make on a Multiple-Response Slide

 

I suggest you create your slide and program it as best you can. Then, if you still need help, upload a copy of a .story file with just that slide for troubleshooting.