Before becoming romantically involved with a coworker, you should

apply for another job at another place.

find out if it would bother your coworkers.

carefully consider possible present and future consequences.

correct!

get your boss’s permission first.

Before becoming romantically involved with a coworker, you should carefully consider possible present and future consequences.
I believe that you should think it through if you want to pursue a relationship with a coworker, because, what if break up with them on a bad note, but you adore your job? Going to work may become a nightmare for you. Your coworkers have nothing to do with your personal life, and your boss cannot forbid you to date anyone outside of workplace. You shouldn't look for a new job just because you are attracted to your coworker either.