I voted for the first option, since the traumatic breakup between the two caused Leon's life to be spared as he entered Raccoon City.
Ada is a tease and Leon has no future with her; he is foolish for even pursuing her. Claire has never shown interest in him whatsoever, and anything he did with Ashley would have been unprofessional (and he knew it). Manuela was too young, and he flirted with Hunnigan to relieve the stress of his mission to Spain. Helena was completely asexual, so the only other choice is Angela, who was obviously legitimately interested in Leon. But the first option is funnier.