This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Forensic Medicine
[{'content': "In organophosphorus compound poisoning, organophosphorus compound actions are - \nSelect and explain. \nA. Phosphorylates enzyme, B. Irreversibly inhibit cholinesterase, C. Oximes effective when given beyond 24 hours, D. Atropine can't reverse in early stage", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mechanism of Action Organophosphorus compounds are inhibitors of acetylcholinesterase by phosphorylating the enzyme. Acetyl cholinesterase is required to hydrolyse acetylcholine to choline and acetic acid As a result, there is accumulation of acetylcholine with continued stimulation of local receptors and eventual paralysis of nerve or muscle . Organophosphate intoxication leads to characteristic end-plate abnormalities that reflect the degree of AchE inhibition and increase in Ach concentration at the neuromuscular junction. REF;THE SYNOPSIS OF FORENSIC MEDICINE:KS NARAYANA REDDY;28th EDITION;PAGE NO 291', 'role': 'assistant'}]