The molecule, which is the initiator of cataract formation in the eye lens and whose 1-phosphate derivative is responsible for the liver failure, is

Galactitol Galactitol and sorbitol both can cause cataract. But there is one more information in the question, i.e. 1-phosphate of that metabolic is responsible for the liver failure. Galactose-1-phosphate cause liver failure in galactosemia. So, the examiner is asking about cataract in galactose