How to make quiz slide as accessible compliant?

Accessibility is a broad topic. Generally, question slides are already accessible unless you have added something else like images or additional objects that contain text. I usually include additional instructions for persons with disabilities to easily navigate these slides. You would probably benefit by reviewing one of the more recent webinars on the topic. Here's one: https://elearning.adobe.com/2021/09/template-based-authoring-workshop-by-kevin-siegel-compliance-soft-skills-training-using-quick-start-projects/