Task: Inferred Class Relation Reasoning (ontology: Sciences/Biology)

After reasoning, which of the following classes is one valid superclass of 'ferredoxin-NADP+ reductase activity'?

A. nephrocyte differentiation
B. obsolete trans-zeatin-O-glucoside UDP glycosyltransferase activity
C. rod bipolar cell differentiation
D. catalytic activity

Answer: catalytic activity