On initial radio contact with an ATS unit the pilot shall transmit the
Why this is the answer
Per the TC AIM call-sign procedure, the first call to an ATS unit gives the manufacturer's name or aircraft type plus the last four letters of the registration spoken in phonetics — not three letters and not the whole registration.
Reference
TC AIM-COM– Call Signs / Civil Aircraft
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.