This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Muscle relaxants, Subject name: Anaesthesia
Which of the following muscle relaxant has the maximum duration of action 
Select and explain. 
A. Atracurium, B. Vecuronium, C. Rocuronimum, D. Doxacurium
D: Doxacurium
Answer: D: Doxacurium 
Explanation: Non-depolarising blockers : long acting (>50min): d-tubocurare , pancuronium, doxacurium, pipecuronium Intermediate acting(20-50mins) : Vecuronium, Atracurium, cisatracurium, rocuronium. Sho acting(<20mins) : Mivacurium, Rapacuronium.