Which sentence from the text BEST explains why Snape mistreated Harry?

A
Snape, however, treats many of them disrespectfully, antagonizing Harry and his friends while favoring students who bully others.

B
Snape eventually drifted toward evil and tried to impress Lily by dabbling in danger.

C
As a consequence, Snape was jealous of James and Lily's happiness.

D
At the end of the Harry Potter series, Snape gives his life to protect Harry Potter.