“In your previous experiences - either through work, studies or interests - when have you spotted a commercial opportunity? What did you do with the idea? What was the outcome and what did you learn from this?”
(The job is HR internship, it’s one of the few online application questions)
I’m completely blanking 
what sort of thing do you think they’re looking for?
I’ve only ever worked in retail, and I do sell second hand clothes online in my spare time but that hardly sounds relevant/interesting 😩