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

The property 'produces' applies to instances of 'material entity', and 'chemical entity' is a subclass of 'material entity'. Which class can appear as the value of 'produces' for instances of 'chemical entity'?

A. present
B. variant
C. material entity
D. Bronsted acid

Answer: material entity