Hotspot Question

Don't use the standard hotspot question. Instead, do this: 

• Add 99%-transparent shapes over the areas you want to be clickable.
  • I suggest you give these shapes a Selected state, so users will see when a shape has been clicked.
• Convert the slide to a Freeform Pick One question.
• In Form View, indicate the shapes that should be clickable and which on is correct. 
• Only areas covered by the designated shapes will be clickable. 

Here's more info about Freeform questions: https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-convert-existing-slide-to-freeform-interaction