This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': '35 yr old female with ptosis & proximal muscle weakness. Test to be done for diagnosis - (REPEATED) \nSelect and explain. \nA. none, B. Muscle biopsy, C. CPK level, D. EMG', 'role': 'user'}, {'content': "Answer: D \nExplanation: Harrison's principles of internal medicine 17t edition. *Single fibre electromyography ,blocking and jitter ,with normal fiber density,confirmatory.", 'role': 'assistant'}]