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

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

A. Liebigite
B. Percylite
C. area
D. Theophrastite

Answer: area