This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Edrophonium test is helpful in diagnosing 
Select and explain. 
A. Marcus gunn jaw winking ptosis, B. myasthenia gravis, C. Blepharophismosis syndrome, D. parkinson's
B: myasthenia gravis
Answer: B: myasthenia gravis 
Explanation: Ref: HL Sharma 3rd ed pg no: 142 edrophonium is very sho acting which helps in differentiating myasthenia and cholinergic crisis