This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lens, Subject name: Ophthalmology
The molecule which is the initiator of cataract formation in the lens of the eye and whose 1-phosphate derivative is responsible for liver failure is 
Select and explain. 
A. Sorbitol, B. Galactitol, C. Inositol, D. Mannitol
B: Galactitol
Answer: B: Galactitol 
Explanation: Ans. (b) GalactitolRef: American Academy of Ophthalmology, BSCS, Section 11/ p. 61In Classic Galactosemia (AR) defect in galactose 1-phosphate uridyltransferase (Gal-1-PUT), results in inability to convert galactose to glucose.Galactose accumulates with further metabolic conversion to galactitol/dulcitol (responsible for cataract) and galactose -1- phosphate (responsible for liver failure).