An otherwise healthy 50-year-old man is brought to your office, located in a small town in the foothills of the Appalachian mountains, by his daughter. The daughter reports that her father has been more lethargic than usual, and she states that she has seen him go into the backwoods and return obviously inebriated. You suspect that he is drinking moonshine from a homemade still and that it is leaching poisonous metals/substances into the distillate.
The patient is morose and has difficulty answering questions. The rest of the physical exam uncovers no other abnormalities.
The blood gas analysis shows a pH of 7.3, a pCO2 of 30 mm Hg, and a bicarbonate of 15 mEq/L. Further laboratory testing revealed sodium of 140 mEq/L and a chloride of 100 mEq/L.

What is the most likely diagnosis?
a. Metabolic acidosis due to ingestion of toxic substances
b. Respiratory alkalosis due to hyperventilation
c. Metabolic alkalosis due to excessive vomiting
d. Respiratory acidosis due to opioid overdose