Task: Property Constraint Reasoning (ontology: Earth_Environment/OBOE)

The property 'has qualifier' applies to instances of 'Measured Characteristic', and 'Mass' is a subclass of 'Measured Characteristic'. Which class can appear as the value of 'has qualifier' for instances of 'Mass'?

A. Characteristic Qualifier
B. Observation Collection
C. Standard
D. Entity

Answer: Characteristic Qualifier