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: Unknown
[{'content': 'Root value of knee-jerk - \nSelect and explain. \nA. L1L2, B. L3L4, C. L5S1, D. S1 S2', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., L3L4ReflexRoot valueBiceps reflex (biceps jerk)C5 C6Supinator reflex (Supinator jerk)C5 C6Triceps reflex (Triceps jerk)C7 C8Knee jerkL3 L4Ankle jerkS1 S2", 'role': 'assistant'}]