Multiple multi choice questions on the same slide

Hi Allan and welcome to E-learning Heroes! 🎉 Thanks for posting your question here! Do you need to track the quiz results in your LMS? If so, you'll need to create each quiz question on a different slide. One of the ways I've gone about this is to have the music play until the learner selects an answer. Then they get feedback visually and audibly if they got it right/wrong. Here's an example game I built of what that looks like: Storyline: Gamified Quiz Template With Timer

If you don't need to keep track of results in an LMS, you can add the questions to layers. I'm not entirely sure what you mean by the previous answer gets greyed out, but this interactive video download (the Medical video one) shows one way to go about including questions and feedback on layers. Just an idea!