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
The first neuromuscular blocker- 
Select and explain. 
A. Succinylcholine, B. d-tubocurare, C. Atracurium, D. Doxacurium
B: d-tubocurare
Answer: B: d-tubocurare 
Explanation: The first agent to be used was d-tubocurare the purified and standardized product of plant chondrodendron tomentosum.