<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 3-week old boy is brought to the physician for the evaluation of lethargy, recurrent vomiting, and poor weight gain since birth. Physical examination shows decreased skin turgor and a bulging frontal fontanelle. Serum studies show an ammonia concentration of 170 μmolL N 30 and low serum citrulline levels. The oral intake of which of the following nutrients should be restricted in this patient?? A: Fructose, B: Protein, C: Vitamin A, D: Gluten, E: Lactose,  <response>: This is a clinical vignette describing a 3-week old infant with symptoms of lethargy, vomiting, poor weight gain, dehydration, and an enlarged fontanelle since birth. The lab findings show hyperammonemia and low citrulline. This presentation is most consistent with a urea cycle disorder, likely ornithine transcarbamylase OTC deficiency. OTC deficiency leads to inability to convert ammonia to urea, thus resulting in hyperammonemia. Low citrulline levels also point towards OTC deficiency. Dietary management for OTC deficiency involves protein restriction to reduce nitrogen load. Additionally, some patients are placed on special formulas low in protein. Of the answer choices, protein restriction would be most appropriate. Fructose, vitamin A, gluten, and lactose restriction would not be specifically indicated.B: Protein 