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': 'Myaesthenia gravis is associated with: \nSelect and explain. \nA. Decreased acetylcholine at nerve endings, B. Decreased myosin, C. Absent troponin C, D. Decreased myoneural junction transmission', 'role': 'user'}, {'content': "Answer: D \nExplanation: Answer is D (Decreased Myoneural junction transmission): The primary defect in Myaesthenia gravis is decreased transmission across the myoneural junction due to decrease in the number of Acetylcholine receptors. The fundamental defect is Myaesthenia gravis is a decrease in the number of Acetylcholine Receptors at the postsynaptic muscle membrane, which results in decreased efficiency of neuromuscular transmission' -- Harrison", 'role': 'assistant'}]