Need to make slide with 3 correct answers, each with different feeback

This post provides a different approach that might work for you: 

https://community.articulate.com/discussions/articulate-storyline/tip-create-a-pick-one-question-with-multiple-correct-answers 

Also, if you want to give feedback based on the user's answer, use variables to track what they selected. Then show different feedback text based on their answers by using triggers with conditions.

The various feedbacks could be shown using different states for the default feedback text box. Or it could be done by giving all the feedback options an Initial state of Hidden, and then showing the appropriate one based on the variables. 

The post below isn't about your exact situation. But it does provide some guidance about showing different feedback based on the value of a variable:

• https://community.articulate.com/discussions/articulate-storyline/tip-give-different-try-again-feedback-after-the-2nd-attempt