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

The property 'has role' applies to instances of 'independent continuant', and 'L-phenylalaninium' is a subclass of 'independent continuant'. Which class can appear as the value of 'has role' for instances of 'L-phenylalaninium'?

A. role
B. alpha-amino-acid residue
C. circadian rhythm
D. physical quality

Answer: role