To ask a question with a sarcastic tone of voice because the answer to the question is obvious. It’s one of the questions that does not need to be asked therefore asking it with proper tone (not overly dramatic) is done with the goal being to draw a light chuckle.
He wapproached the fast food counter with the idea of leading off with some sarquesm. "Are your fries really THAT good?" he asked sarquestically.