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

The property 'has area' applies to instances of 'geometrical object 2d', and 'crescent' is a subclass of 'geometrical object 2d'. Which class can appear as the value of 'has area' for instances of 'crescent'?

A. area
B. Zircophyllite
C. Ferroferritschermakite
D. Umbite

Answer: area