Q. A 70-year-old man is brought to the emergency department 30 minutes after a sudden right arm weakness and difficulty speaking. He has a history of hypertension and coronary artery disease. He takes lisinopril, atorvastatin, and aspirin. He has smoked two packs of cigarettes daily for the last 30 years, and he does not drink alcohol. His BP is 155/88 mmHg, HR is 100/min, RR is 20/min, and his temperature is 37.2 °C. On examination, his muscle strength is 2/5 in the right upper extremity, 4/5 in the right lower extremity, and normal muscle strength on the left side. He has a right facial droop. The patient is frustrated as he understands what others say but cannot speak fluently. What is the most likely cause of these symptoms?