question: Q:A 68-year-old man is brought to the emergency department by ambulance after he fainted in the supermarket. He recently had 2 days of gastroenteritis, but did not come to the hospital for treatment. He also recently arrived in Denver for a vacation, but normally lives in Florida. His past medical history is significant for morbid obesity and heavy alcohol use. Arterial blood gas and serum chemistry results are shown below:
  
  Sodium: 138 mEq/L
  Chloride: 121 mEq/L
  Bicarbonate: 8 mEq/L
  pH: 7.25
  PaCO2: 20 mmHg
  
  Which of the following etiologies is most likely responsible for this patient's findings?? 
  {'A': 'Altitude sickness', 'B': 'Diarrhea', 'C': 'Ethanol consumption', 'D': 'Hypoventilation', 'E': 'Vomiting'},