This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parkinsonism and other movement disorders, Subject name: Medicine
[{'content': 'Essential tremor does not exist in: \nSelect and explain. \nA. Hand, B. Head, C. Lips, D. Voice', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Essential tremor Most common of all movement disorder. Higher in frequency and lower in amplitude than the tremor of PD. May be a form of enhanced physiological tremor, but recent evidence suggests a cerebellar abnormality. Often familial. Postural and action tremor that tends to affect the hands, head, and voice. Made worse by anxiety.', 'role': 'assistant'}]