I also voted for Jaheira for romances, but for me that was a vote by process of elimination: all the other companions got eliminated by my preferences until only Jaheira was left. But I'm really not at all interested in a romance with her. As I've been saying, I don't have a viable romance option in the game.
Ah. Well I don't know if that was clear enough, but this question asked for at most 4 answers. So you could have chosen less than 4. Including 0 obviously. No question is mandatory.
Anyway, I was kind of surprised myself when I listed her with my 4th pick, but the more I think of it, the more I think that I'd be really interested in explore her romance, and that I'd be a bit disappointed if it turns out she's not romanceable.
When I specifically put 0 as number of partners, I was mostly thinking of people who don't want romances (/"dating sims") in their fantasy adventures. But I'm glad it also covers players who would have liked one, but don't find the companions appealing enough.