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

The property 'orthogonal to' applies to instances of 'direction', and 'inward' is a subclass of 'direction'. Which class can appear as the value of 'orthogonal to' for instances of 'inward'?

A. granule
B. direction
C. radiative cooling
D. upper level

Answer: direction