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: Physiology
[{'content': 'Muscle spindle detects ? \nSelect and explain. \nA. Tension, B. Length, C. Proprioception, D. Pressure', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Length", 'role': 'assistant'}]