What is the answer to this radio question?

A few years ago I was driving to work and heard a question on the radio. They were giving away a prize for the caller with the right answer. I didn’t get to hear the answer because I had to go to work. It’s been driving me nuts ever since.

The question was “What smell/scent/aroma do people like the most?”

Is there one single researched answer to this question?

Answers that were given, but incorrect were vanilla, chocolate, baking bread, baking cookies, clean laundry, and lemon. There may have been others that I’m not recalling. Also, they finally gave the hint, after many wrong answers, that it was commonly found in the kitchen.

Any ideas? Is this like some solid fact that I can find somewhere?