<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 presents to the ER with progressive dysphagia over the course of 3 months and a new onset fever for the past 24 hours. The temperature in the ER was 39.5C 103.1F. There are white exudates present on enlarged tonsils Grade 2. Routine blood work reveals a WBC count of 89,000mm3, with the automatic differential yielding a high 90 percentage of lymphocytes. A peripheral blood smear is ordered, demonstrating the findings in the accompanying image. The peripheral smear is submitted to pathology for review. After initial assessment, the following results are found on cytologic assessment of the cells:TdT: positiveCALLA CD 10: positiveWhich of the following cell markers are most likely to be positive as well? ? A: CD 8, B: CD 2, C: CD 7, D: CD 19, E: CD 5,  <response>: This is a clinical vignette describing a 7-year-old boy with progressive dysphagia, fever, tonsillar enlargement, and lymphocytosis on bloodwork. The peripheral blood smear shows lymphoblasts, and initial immunophenotyping shows positivity for TdT and CALLACD10, which are markers of lymphoblastic leukemia. The key here is that TdT and CD10 positivity indicate this is likely a case of acute lymphoblastic leukemia ALL. CD10 is a common acute lymphoblastic leukemia antigen. TdT is a marker expressed in precursor cells and positive in most cases of ALL. So we need to determine which cell marker is most consistent with the diagnosis of ALL based on the clinical presentation and initial workup.D: CD 19 