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

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

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

Answer: Achievement