Were you asked at a job interview
or on a test?
If it was a test I'd like to know the options, every 5 - 10 - 15 minutes?
In a job interview I would say I would closely monitor the patient...as in not even leave their bedside....for maybe ten minutes. I hate to put an exact time, sometimes you have to go with your "gut" feeling. Then gently try to arouse them. I would gently tap or shake them ask how they were. I would expect, accept, a mumbled response and eye opening. If they were not responsive to that..... I still would not leave their bedside and maybe give them five more minutes. If they still had no response to gentle...or even slightly more "aggressive", attempts by me to arouse them I might, or would, notify anesthesia.
This is assuming they are on oxygen, pulse oximeter, cardiac monitoring, blood pressure monitoring, and their vital signs were stable.