My opinion is that true attraction is chemical. I believe that preferences can change based on on nurture / biology and social construct, but when I think of the various ways people become attracted to someone, it seems like it has to be a chemical reaction. I've observed how drinking or some drugs alter someone's attraction to people, how someone could meet someone and not be attracted to them until they get to know them, how there are various forms of attraction outside of being visual, and how someone might find someone attractive one second, then not the next second. I think a chemical reaction could cover all those bases.
I place nurture/biology as a close second because I feel like there are things about someone's life that influences their attraction, but the reason I placed it in second is because it seems like this influences more of their preferences and less of them literally being attracted to someone. Chemical reaction and nurture/biology go hand in hand. For example, growing more attracted to someone over time could be because you are noticing more and more things you love about them and the things you are noticing subconsciously reminds you of your dad/mom.
The reason I put social constructs last is because even though beauty standards are impactful to society, the minority or people reach those standards, yet people still are becoming attracted to the majority of people day after day. It's almost like social standards more impactful to how people view themselves than how people view other people. I feel like I need a six-pack to be attractive, but I think you're beautiful just the way you are.
So, my final opinion is that the ultimate form of attraction is a combination of chemicals being released from preferences built on nature/biology. Now that I shared my opinion, what's yours? After you are done thinking, watch this video and see how your thoughts align with science: