question: Q:A 63-year-old man is brought by his wife to the emergency department after he was found with nausea, headache, and agitation 1 hour ago. When the wife left their lakeside cabin earlier in the day to get more firewood, the patient did not have any symptoms. Vital signs are within normal limits. Pulse oximetry on room air shows an oxygen saturation of 98%. Neurologic examination shows confusion and orientation only to person and place. He recalls only one of three objects after 5 minutes. His gait is unsteady. Which of the following is the most effective intervention for this patient's current condition?? 
  {'A': 'Intravenous hydroxycobalamin', 'B': 'Heliox therapy', 'C': 'Hyperbaric oxygen therapy', 'D': 'Intranasal sumatriptan', 'E': 'Intravenous nitroprusside'},