Teenage brothers Michael (Jason Patric) and Sam (Corey Haim) move with their mother (Dianne Wiest) to a small town in northern California. While the younger Sam meets a pair of kindred spirits in geeky comic-book nerds Edward (Corey Feldman) and Alan (Jamison Newlander), the angst-ridden Michael soon falls for Star (Jami Gertz) -- who turns out to be in thrall to David (Kiefer Sutherland), leader of a local gang of vampires. Sam and his new friends must save Michael and Star from the undead.
Best is the correct answer because that is the correct superlative form of the adjective "good". Here we use the superlative to show that he was the best of all the students.