Task: Property Constraint Reasoning (ontology: Arts_Media_Entertainment/VideoGameOntology)

The property 'unlocks achievement' applies to instances of 'instantaneous event', and 'game event' is a subclass of 'instantaneous event'. Which class can appear as the value of 'unlocks achievement' for instances of 'game event'?

A. Game
B. PopulatedPlace
C. Achievement
D. Agent

Answer: Achievement