This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which one of the following drugs is not a non depolarizing competitive neuromuscular blocker? 
Select and explain. 
A. Doxacurim, B. Decamethonium, C. Rocuronium, D. Mivacurium
B: Decamethonium
Answer: B: Decamethonium 
Explanation: None