A

The triad of pinpoint pupils, profuse salivation, and bronchial secretions indicates a cholinergic (organophosphate) toxidrome; the first-line antidote is the muscarinic antagonist atropine, which rapidly reverses bronchorrhea and excessive secretions [Leach, 1953, PMID 13059622; Ibrahim, 2022, PMID 36532913].