The Compounds Below Are Base Pairs Used to Form Supramolecular

Multiple Choice

The compounds below are base pairs used to form supramolecular polymers (Org. Lett. 2011, 240) . They are held together by three intermolecular hydrogen bonds and each contains one intramolecular hydrogen bond. Which atom in structure B forms a hydrogen bond with the circled hydrogen in structure A?

A) 1
B) 2
C) 3
D) 4