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 'astronomical body part' 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 'astronomical body part'?

A. process
B. obsolete porcine meat product
C. transient tracer
D. animal material

Answer: process