Q. A 38-year-old woman is brought to the emergency department by her husband because of a transient loss of vision in the right eye and weakness in her left upper extremity that lasted for 30 minutes. She reports right-sided neck pain and headache prior to the episode. Her vital signs are normal except for hypertension (BP 159/90 mmHg). Neurologic examination shows ptosis and constricted pupil on the right side. Fundoscopy is normal. Motor functions and sensations are intact all over the body. What is the most likely diagnosis?