<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:An investigator is studying vitamin D metabolism in mice. He induces a gene mutation that interferes with the function of an enzyme in the renal proximal tubules that is required for vitamin D activation. He then measures serum levels of various metabolites. Production of which of the following will be impaired in this mouse?? A: Ergocalciferol, B: 25-hydroxyvitamin D, C: Cholecalciferol, D: 1,25-hydroxyvitamin D, E: 7-dehydrocholesterol,  <response>: This is a question about vitamin D metabolism and the effects of a mutation affecting an enzyme involved in vitamin D activation in the kidneys. It is asking which metabolite will have impaired production due to this mutation. Based on the information provided, the mutation affects an enzyme required for vitamin D activation in the proximal tubules of the kidneys. This suggests the enzyme is likely involved in the conversion of a vitamin D precursor to an active form. The choices include vitamin D precursors cholecalciferol, ergocalciferol as well as hydroxylated forms 25-hydroxyvitamin D, 1,25-hydroxyvitamin D. 7-dehydrocholesterol is a precursor to vitamin D production.Since the enzyme is involved in activation, it is likely required for the hydroxylation steps. Therefore, the mutation would be expected to impair production of 1,25-hydroxyvitamin D, the active form of vitamin D produced in the kidneys.D: 1,25-hydroxyvitamin D 