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

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

A. fuel
B. hydrocarbon biosynthetic process
C. plant structure development stage
D. material entity

Answer: material entity