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

Which of the following classes is one valid superclass of 'glutamyl-tRNA(Gln) amidotransferase complex'?

A. (R,S)-reticuline 7-O-methyltransferase activity
B. 12-beta-hydroxysteroid dehydrogenase (NADP+) activity
C. 2,4,6-trinitrotoluene metabolic process
D. intracellular protein-containing complex

Answer: intracellular protein-containing complex