This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Which of the following is used as an antidote to nicotine poisoning 
Select and explain. 
A. Neostigmine, B. Atropine, C. Phentolamine, D. Trimethaphan
D: Trimethaphan
Answer: D: Trimethaphan 
Explanation: Ref: HL Sharma 3rd ed pg:195 Nicotine is an agonist for NN receptors Ganglion blockers are antagonists for NN receptors eg: hexamethonium, trimethaphan, Mecamylamine etc