Identify the correct sentence.

A. You parked your car on the sidewalk at a time when no parking at all was allowed. This is why you are getting a parking ticket.

B. You parked your car on the sidewalk at a time when no parking at all was allowed. That is why you are getting a parking ticket.

C. You parked your car on the sidewalk at a time when no parking at all was allowed, which is why you are getting a parking ticket.

D. You parked your car on the sidewalk at a time when no parking at all was allowed. So your ticket is for parking at the wrong time and in the wrong place.