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': 'Features of pyramidal tract lesion are all except \nSelect and explain. \nA. Clasp knife rigidity, B. Involuntary movements, C. Positive Babinski sign, D. Exaggerated reflexes & increased tone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Babinski sign is the sure sign of pyramidal tract/corticospinal lesion.\nSpasticity and exaggerated tendon reflexes are due to extrapyramidal lesions. \nSince pyramidal lesion occurring alone is rare, extrapyramidal lesions also may be seen. \nRigidity seen is clasp knife type.', 'role': 'assistant'}]