<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 4-year-old boy is brought to the emergency department with intense crying and pain in both hands after playing with ice cubes. His mother denies any preceding trauma. The temperature is 37.0C 98.6F, the blood pressure is 9055 mm Hg, and the pulse is 100min. The physical examination shows swollen dorsa of the hands and scleral icterus. The laboratory tests show hemoglobin of 10.1 gdL and unconjugated hyperbilirubinemia. The cellulose acetate electrophoresis shows 60 HbS and absence of HbA. Which of the following can reduce the recurrence of the patients current condition?? A: Avoidance of sulfa drugs, B: Vaccinations, C: Hydroxyurea, D: Folic acid, E: Allopurinol,  <response>: This is a clinical vignette describing a 4-year-old boy with symptoms of hand pain and crying after exposure to cold temperatures. The description of swollen hands, scleral icterus, anemia, and unconjugated hyperbilirubinemia points to a diagnosis of sickle cell disease. The question asks about reducing recurrence of the vaso-occlusive crisis that the patient is experiencing. Hydroxyurea increases fetal hemoglobin production which reduces sickling of red blood cells, thus reducing frequency of vaso-occlusive crises. Avoidance of sulfa drugs prevents drug-induced sickling but does not reduce baseline frequency of crises. Vaccinations help prevent infections that could trigger crises but do not affect baseline frequency. Folic acid supplementation reduces risk of anemia but does not affect sickling. Allopurinol reduces uric acid levels in conditions like gout and does not affect sickling.C: Hydroxyurea 