<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 7-year-old boy is brought to the pediatrician by his parents due to pubic hair growth and changes in his voice. He has been developing in the 98th percentile for his age. His vaccination is up-to-date. The patients blood pressure is within the 60th percentile for his age. Physical examination reveals pubic and armpit hair, and Tanner stage 2 characterized by enlarged scrotum and testes. Laboratory findings are significant for the following:Hemoglobin 13.1 gdLHematocrit 39.7Leukocyte count 8,500mm3Neutrophils 65Lymphocytes 30Monocytes 5Mean corpuscular volume 82.2 μm3Platelet count 20,000mm3Urine creatinine clearance 98 mLminSerum 17-hydroxyprogesterone 313 ngdL normal 110 ngdLWhich of the following enzymes is most likely to be defective in this patient?? A: 17-α-hydroxylase, B: 5-α-reductase, C: 21-hydroxylase, D: 11ß-hydroxylase, E: Aromatase,  <response>: This is a clinical vignette describing a 7-year-old boy with signs of precocious puberty, including pubic and armpit hair growth, enlarged scrotum and testes, and changes in his voice. The key lab finding is an elevated 17-hydroxyprogesterone level, which along with his physical exam findings, points towards congenital adrenal hyperplasia CAH. The choices list various enzymes involved in steroidogenesis. In CAH, there is a defect in an enzyme required for cortisol production, leading to shunting of precursors towards androgen production and virilization. The classic enzyme deficiency in CAH leading to this presentation is 21-hydroxylase deficiency. Therefore, the answer is C.C: 21-hydroxylase 