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

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

A. haze
B. direction
C. net primary productivity
D. clot

Answer: direction