mrcem2-1259

A 55-year-old man with a history of hypertension arrived at the emergency department with a sudden and severe occipital headache accompanied by vomiting and neck stiffness. There is no reported head injury. Upon clinical examination, the patient has a temperature of 37ºC, a respiratory rate of 18 per minute, a pulse of 88 beats per minute, and a blood pressure of 160/100. The physician observes a lateral and inferior deviation of the left eye with a dilated pupil and drooping of the left upper eyelid.

What is the SINGLE most likely diagnosis?