The pilot of an arriving VFR flight shall make initial radio contact with a control tower in Class C airspace
Why this is the answer
Class C requires VFR aircraft to be cleared in, so initial radio contact with the tower must be made prior to entering the Control Zone (CARs 601.08; TC AIM-RAC). Contacting ATC only after entry would mean operating there without the required clearance.
Reference
CARs 601.08 – VFR Flight in Class C Airspace TC AIM-RAC – Class C Airspace TC AIM-RAC – Arrival Procedure – Controlled Airports, Initial Contact
Question reproduced verbatim from Transport Canada’s PSTAR Study and Reference Guide (TP 11919E). The answer key is Transport Canada’s; the explanation is ours.
A study aid — not a substitute for the official guide, the CARs, or your instructor.