The wing tip vortices generated by a heavy aeroplane can cause a lighter aircraft encountering them to
Why this is the answer
Per TC AIM-AIR (Wake Turbulence / Vortex Characteristics), a heavy aeroplane's vortices can produce roll rates beyond a light aircraft's control authority, force it to descend even at full power, and even cause structural damage — so any of these outcomes is possible.
Reference
TC AIM-AIR – Wake Turbulence TC AIM-AIR – Wake Turbulence / Vortex Characteristics / General
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.