Task: Class Relation Understanding (ontology: Sciences/Biology)

Which of the following classes is one valid superclass of 'purine ribonucleoside diphosphate metabolic process'?

A. 4-[1-hydroxy-2-(methylamino)ethyl]benzene-1,2-diol
B. CD14 molecule (chicken)
C. Crustacea
D. ribonucleoside diphosphate metabolic process

Answer: ribonucleoside diphosphate metabolic process