Final answer:
The correct answer is A. acetylcholine; parasympathetic. Cholinergic drugs mimic acetylcholine which affects the parasympathetic nervous system.
Step-by-step explanation:
Cholinergic drugs mimic the action of the neurotransmitter acetylcholine, which is part of the action of the parasympathetic nervous system. Therefore, the correct answer is A. acetylcholine; parasympathetic. Acetylcholine is the primary neurotransmitter used by the parasympathetic nervous system, and it works by binding to muscarinic receptors on target organs. Muscarinic agonists, or parasympathomimetic drugs, act similarly to acetylcholine released by parasympathetic postganglionic fibers, enhancing the parasympathetic signals. On the other hand, the sympathetic system is influenced by adrenergic molecules like norepinephrine and epinephrine, which are mimicked by sympathomimetic drugs