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

Which of the following classes is one valid superclass of 'N-[[(3R,9S,10R)-16-(dimethylamino)-12-[(2S)-1-hydroxypropan-2-yl]-3,10-dimethyl-13-oxo-2,8-dioxa-12-azabicyclo[12.4.0]octadeca-1(14),15,17-trien-9-yl]methyl]-N-methyl-4-pyridinecarboxamide'?

A. ((2-bromo-4-methylphenyl){6-[(4-{[(2S)-3-(dimethylamino)-2-hydroxypropyl]oxy}phenyl)amino]pyrimidin-4-yl}amino)acetonitrile
B. lactam
C. ((13)C)carbon dioxide
D. ((2-bromo-4-methylphenyl){6-[(4-{[(2R)-3-(dimethylamino)-2-hydroxypropyl]oxy}phenyl)amino]pyrimidin-4-yl}amino)acetonitrile

Answer: lactam