Nicotine is a :ATropane AlkaloidBPhenanthre AlkaloidCPyridine-Pyrrolidine AlkaloidDQuinoline Isoquinoline AlkaloidAnswer: C. Pyridine-Pyrrolidine Alkaloid Read Explanation: Nicotine is a pyridine-pyrrolidine alkaloid, a specific type of alkaloid characterized by its chemical structure. This structure consists of two nitrogen-containing heterocyclic rings: a pyridine ring and a pyrrolidine ring connected by a carbon-carbon bond. Read more in App