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

The property 'relation between physical entity and a process or stage' applies to instances of 'independent continuant', and 'sodium(1+)' is a subclass of 'independent continuant'. Which class can appear as the value of 'relation between physical entity and a process or stage' for instances of 'sodium(1+)'?

A. occurrent
B. obsolete pigmentation
C. obsolete fast muscle cell somite 30
D. greenhouse gas

Answer: occurrent