This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Carbohydrate Metabolism, Subject name: Pediatrics
A 3-day-male baby vomits everything he feeds, has a distended abdomen and diarrhea. On examination, he has bilateral cataract. The urine is positive for Benedict's test for reducing substance. Which of the following is the probable underlying diagnosis? 
Select and explain. 
A. Hereditary Fructose intolerance, B. Phenylketonuria, C. Galactosemia, D. Von Gierke disease
C: Galactosemia
Answer: C: Galactosemia 
Explanation: The given clinical features:- Vomiting Abdominal distension Diarrhea Presence of reducing substance in urine, in a 3-day-old neonate, who is probably on exclusive breast feeding, suggests diagnosis of Galactosemia. In a confirmed case of galactosemia- breast milk is contraindicated Lactose breaks down to glucose & galactose- galactose cannot be digested in Galactosemia.