Which of the following compounds is a heterocyclic base?A) propanoneB) propyl methanoateC) purineD) ethanalE) sodium benzoate

The heterocyclic base among the given compounds is C) purine.

Heterocyclic compounds are organic compounds (those containing carbon) that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring.

Purine is a heterocyclic compound. It is an aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines, including substituted purines and their tautomers, are the most widely occurring nitrogen-containing heterocycle in nature.

The other compounds listed - propanone, propyl methanoate, ethanal, and sodium benzoate - are not heterocyclic bases.