Which of the following is an example of a naturally occurring alkaloid?

Pilocarpine and nicotine are examples of naturally occurring alkaloids. Alkaloids are a class of nitrogen-containing compounds that are primarily found in plants and often have significant pharmacological effects on humans and animals.

Pilocarpine is derived from the leaves of the shrub Pilocarpus jaborandi and has been used therapeutically for its ability to stimulate salivation and lacrimation, particularly in the treatment of dry mouth and glaucoma.

Nicotine is also a naturally occurring alkaloid, primarily found in tobacco plants. It acts as a stimulant and has notable effects on the nervous system, contributing to both its addictive properties in tobacco products and its potential therapeutic uses in certain contexts.

Carbachol, on the other hand, is a synthetic choline ester and does not belong to the category of naturally occurring alkaloids. It acts on both muscarinic and nicotinic receptors but is manufactured rather than derived from natural sources.

Thus, selecting both pilocarpine and nicotine as examples of naturally occurring alkaloids is correct, as they both are derived from plant sources and classified within the broader group of alkaloids.