You should have allowed multiple options. It varies a lot with me. I've fantasized about sex with my wife probably more than anything else, both things we did years ago, and also things we did in our last session. I also fantasize about things I did with previous partners, especially the ex-gf who was the most passionate about blowjobs, and who loved to swallow.
I also fantasize about fucking, about getting fucked, about giving oral to men, about giving oral to women, about getting oral, about anal, humiliation, bondage, dominating, submitting — and LOTS of other things! Sometimes, many different things flash through my mind during the same session.
I seldom fantasize about anything sweet or romantic — except if it's with one of my best friends' wives! I always try to think of something else when those thoughts come, but lust has a mind of its own.