Question

Please Help! Will fan and medal! Read the proposition and the implication shown below.
"If the lights are off, there is no one inside."

Which statement is a contrapositive to the proposition and logically equivalent to it? side.

A. If the lights are not off, there is someone in.
B. If there is no one inside, the lights will not be on.
C. If the lights are on, there is someone inside.
D. If there is someone inside, the lights will be on.

I think it's C but I'm not sure