This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
Which of the following is the shoest acting competitive neuromuscular blocking agent? 
Select and explain. 
A. Pancuronium, B. Doxacurium, C. Mivacurium, D. Vecuronium
C: Mivacurium
Answer: C: Mivacurium 
Explanation: Mivacurium is the shoest acting non-depolarizing SMR because it is metabolized by an esterase. It can be used as an alternative to SCh for endotracheal intubation.