You are answering a USMLE-style medical question. Question: A 62-year-old man comes to the physician because of worsening involuntary movements of both arms for the past 7 months. He reports that certain daily activities have become more difficult to perform. His father had a similar condition that was treated with medications. The patient appears anxious. Vital signs are within normal limits. Examination shows a low-amplitude tremor bilaterally when the arms are outstretched that worsens when reaching out to grab a pen. Muscle strength and tone is normal bilaterally. Deep tendon reflexes are 2+ bilaterally. On mental status examination, his mood is good. His speech is normal in rate and rhythm. Which of the following is the most appropriate next step in management? Options: A) Deep brain stimulation B) Thalamotomy C) Levodopa and carbidopa therapy D) Propranolol therapy Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.