<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 45-year-old man presents with lethargy, muscle aches, and dry skin. He is underweight and has very particular eating habits. Physical examination reveals swollen bleeding gums, cracked lips, petechiae, perifollicular hemorrhage, and corkscrew hairs. Laboratory tests reveal a nutritional deficiency. Which of the following is the key function of the most likely deficient nutrient?? A: Precursor of serotonin, B: Hydroxylation of lysine and proline residues in collagen synthesis, C: Component of the visual pigment rhodopsin, D: Cofactor in carboxylase reactions, E: Gamma-carboxylation of glutamate residues in clotting factors,  <response>: Based on the symptoms described in the question stem, this patient likely has a nutritional deficiency leading to scurvy. The symptoms of lethargy, muscle aches, dry skin, bleeding gums, petechiae, and perifollicular hemorrhage are classic manifestations of scurvy caused by vitamin C deficiency. The particular eating habits and underweight status also point towards a nutritional deficiency. Vitamin C is essential for collagen synthesis, so a deficiency leads to corkscrew hairs and bleeding into the skin and mucous membranes. The key function of vitamin C is as a cofactor in hydroxylation reactions involved in collagen synthesis.B: Hydroxylation of lysine and proline residues in collagen synthesis 