Who is most responsible for the deaths of romeo and Juliet?

There families are most responsible because they would not let Romeo and Juliet be together, which brought them to killing themselves.

Friar Lawrence and Tybalt, because Tybalt got into a duel with Mercutio and romeo got into it giving tybalt time to kill mercutio. and friar lawrence because he told juliet that romeo loved rosaline before and the next day he was in love with her