This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
A few days after bih, a child becomes lethargic, refuses feeds and vomits during breast feeding. On examination he is pot bellied. Benedict's test is positive in urine. What is the likely reducing sybstance present in urine: 
Select and explain. 
A. Glucose, B. Fructose, C. Sucrose, D. Galactose
D: Galactose
Answer: D: Galactose 
Explanation: D i.e. Galactose