This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuromuscular Blocker, Subject name: Anaesthesia
First neuromuscular blocker to be used clinically:- 
Select and explain. 
A. D-tubocurare, B. Succinylcholine, C. Doxacurium, D. Mivacurium
A: D-tubocurare
Answer: A: D-tubocurare 
Explanation: d-tubocurare is naturally occurring neuromuscular blocker and was first neuromuscular blocker to be used clinically. It is extract of curare plant. Not in clinical use since it release huge amount of histamine and has very long duration of action.