Verbal Aptitude

A health survey notes that farmers who drink unpasteurized raw milk report fewer allergies than urban dwellers who drink pasteurized milk. Concluding that unpasteurized milk cures allergies overlooks which confounding factor?

Options:

• (A) Rural farm environments expose children early to diverse microbes and animals, which strengthens immune tolerance (the hygiene hypothesis).
• (B) Pasteurized milk contains no calcium.
• (C) Cows produce milk daily.
• (D) Urban residents drink more coffee than farmers.