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

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

A. direction
B. evaporation fog
C. body wave
D. geothermal power process

Answer: direction