In Texas, a Man Showed Up at a Medical Facility

In Texas, a man showed up at a medical facility claiming that he felt drunk when he had not ingested any alcohol. Indeed his blood alcohol measured 0.37, many times the legal limit. Although he was a home brewer, he claimed that this intoxication had been happening often without his drinking any alcohol. Which of these hypotheses and actions might be most useful in diagnosing this problem?

A) His home brew concoctions have created a type of alcohol that lasts a long time. Have him refrain from home brewing for a week and recheck his blood alcohol.
B) He might have recently had a round of antibiotics that killed the bacteria that usually live in his gut and allowed a yeast species to overgrow. Put him on probiotics and a low carb diet for a week and recheck his blood alcohol.
C) The fumes from the alcohol that he is using as a cleaning solution might be getting into his bloodstream. Ask him if he is using alcohol externally.
D) Maybe he feels drunk because he has been eating mushrooms that have sprouted during this very wet weather. Check him for fungal toxins.