Question

What was the first monster Percy Jackson encountered?
A. Minotaur
B. A Fury
C. Medusa

Answer 1

B. A Fury a.k.a Alecto a.k.a  Mrs.Dodds a.k.a his math teacher

Answer 2

The first official monster that Percy Jackson encountered was B. A Fury, considering it was after Percy (to get the Lightning Bolt), during the school trip. The Minotaur and Medusa didn't come till later.