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
Dr. Sunil used edrophonium for differentiating a myasthenic crisis from the cholinergic crisis. He preferred it over other anticholinesterase agents because of its: 
Select and explain. 
A. Shorter duration of action, B. Longer duration of action, C. Direct action on muscle end plate, D. Selective inhibition of true cholinesterase
A: Shorter duration of action
Answer: A: Shorter duration of action 
Explanation: Edrophonium- Short-acting anticholinesterase.
In Myasthenia gravis, edrophonium improves the condition.