The characteristic fruity-smelling breath seen in diabetic ketoacidosis results from the exhalation of:

1. In ketoacidosis, fat breakdown produces ketone bodies including acetoacetic acid, beta-hydroxybutyric acid, and acetone. 2. One of these ketone bodies is volatile and can be exhaled through the lungs. 3. The classic fruity breath odor specifically to exhaled acetone. 4. Lactic acid and ammonia are not described as producing this smell, so they are ruled out. 5. So acetone is correct. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 26 "Fluid, Electrolyte, and Acid-Base Balance", p.1268-1269 §Acid-Base Balance: Ketoacidosis_