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

The property 'causal relation between material entity and a process' applies to instances of 'material entity', and 'layer' is a subclass of 'material entity'. Which class can appear as the value of 'causal relation between material entity and a process' for instances of 'layer'?

A. biomarker
B. animal material
C. process
D. realizable entity

Answer: process