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: Medicine
[{'content': '21 year old female presents with history of mild bilateral ptosis, proximal muscle weakness and easy fatiguability which among the following is best in diagnosing this condition - \nSelect and explain. \nA. Muscle biopsy, B. Edrophonium test, C. Repetitive nerve stimulation, D. Electro myography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]