<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 1-year-old boy presents to the physician with a fever and a persistent cough for the past 5 days. His parents noted that since birth, he has had a history of recurrent skin infections, ear infections, and episodes of pneumonia with organisms including Staphylococcus aureus, Pseudomonas, and Candida. Physical exam is notable for prominent facial scars in the periorbital and nasal regions, which his parents explain are a result of healed abscesses from previous skin infections. A sputum sample is obtained from the patient and the culture grows Aspergillus. Which of the following diagnostic test findings would confirm the patients underlying genetic disease?? A: Complete blood count, B: Dihydrorhodamine test, C: Flow cytometry for CD18 protein, D: Fluorescent in situ hybridization, E: Quantitative serum immunoglobulin test,  <response>: This is a clinical vignette describing a 1-year-old boy with a history of recurrent infections and current fever, cough, and sputum culture positive for Aspergillus. The question asks which diagnostic test would confirm an underlying genetic disease in this patient. Based on the history of recurrent skin, ear, and lung infections with unusual organisms starting early in life, this patient likely has an immunodeficiency disorder. The facial scarring also suggests a disorder involving impaired wound healing. Choice A can be eliminated, as a complete blood count would not confirm the specific genetic disease. Choice B, the dihydrorhodamine test, can detect chronic granulomatous disease, an immunodeficiency disorder characterized by recurrent bacterial and fungal infections. This is a possible answer.Choice C, flow cytometry testing for CD18 protein levels, can confirm leukocyte adhesion deficiency type 1 LAD-1, which causes impaired wound healing and recurrent bacterial infections. This is also a reasonable answer based on the patients history.Choice D, fluorescent in situ hybridization, is a cytogenetic technique that would not confirm an immunodeficiency disorder. This can be eliminated. Choice E, quantitative immunoglobulin testing, could reveal an antibody deficiency but would not confirm the specific genetic disease. This can also be eliminated.B: Dihydrorhodamine test 