This is a case of hereditary fructose intolerance because the age of presentation is after 6 months as after 6 months fructose containing food are introduced into the diet. It occurs due to the deficiency aldolase B enzyme. Aldolase B catalyzes the conversion of fructose- 1,6-bisphosphate into triose phosphate and glyceraldehyde phosphate It leads to profound hypoglycemia and vomiting after consumption of fructose (or sucrose, which yields fructose on digestion). OPTION B is essential fructosuria which is due to the deficiency of fructokinase which conves fructose into fructose-1-phosphate and is an asymptomatic condition. OPTION C is classical galactosemia due to the deficiency of galactose-1 phosphate uridyl transferase and usually presents in the 2nd week of life and not after 6 months and presents with jaundice, hepatomegaly, vomiting, hypoglycemia, seizures, hepatic failure, ascites, splenomegaly, or intellectual disability. OPTION D is galactokinase deficiency and presents with increased galactose levels in serum if the child consumes a high lactose diet.