Task: Property Constraint Reasoning (ontology: Sciences/Biology)

The property 'has skeleton' applies to instances of 'anatomical structure', and 'vestigial structure' is a subclass of 'anatomical structure'. Which class can appear as the value of 'has skeleton' for instances of 'vestigial structure'?

A. circadian rhythm
B. ossification
C. material anatomical entity
D. anti-inflammatory drug

Answer: material anatomical entity