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': 'Following are the features of corticospinal involvement except \nSelect and explain. \nA. Cog-wheel rigidity, B. Spasticity, C. Plantar extensor response, D. Exaggerated deep tendon reflexes', 'role': 'user'}, {'content': 'Answer: A \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. Rigidity seen is clasp knife type.', 'role': 'assistant'}]