<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:An 18-month-old boy of Ashkenazi-Jewish descent presents with loss of developmental milestones. On ocular exam, a cherry-red macular spot is observed. No hepatomegaly is observed on physical exam. Microscopic exam shows lysosomes with onion-skin appearance.What is the most likely underlying biochemical abnormality?? A: Accumulation of ceramide trihexoside, B: Accumulation of galactocerebroside, C: Accumulation of sphingomyelin, D: Accumulation of GM2 ganglioside, E: Accumulation of glucocerebroside,  <response>: This is a clinical vignette describing an 18-month-old boy with loss of developmental milestones, cherry-red macular spot on eye exam, normal liver exam, and onion-skin lysosomes on microscopy. This presentation is classic for a lysosomal storage disease. The choices list different lipid storage molecules. Based on the age, ethnicity, exam findings, and microscopy results, this patient most likely has Tay-Sachs disease, which is caused by accumulation of GM2 ganglioside due to deficiency of hexosaminidase A enzyme. D: Accumulation of GM2 ganglioside 