<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 3-month-old girl is brought to the emergency department because of a 2-day history of progressive difficulty breathing and a dry cough. Five weeks ago, she was diagnosed with diffuse hemangiomas involving the intrathoracic cavity and started treatment with prednisolone. She appears uncomfortable and in moderate respiratory distress. Her temperature is 38C 100.4F, pulse is 150min, respirations are 50min, and blood pressure is 8850 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 87. Oral examination shows a white plaque covering the tongue that bleeds when scraped. Chest examination shows subcostal and intercostal retractions. Scattered fine crackles and rhonchi are heard throughout both lung fields. Laboratory studies show a leukocyte count of 21,000mm3 and an increased serum beta-D-glucan concentration. An x-ray of the chest shows symmetrical, diffuse interstitial infiltrates. Which of the following is most likely to confirm the diagnosis?? A: Bronchoalveolar lavage, B: Urine antigen test, C: DNA test for CFTR mutation, D: CT scan of the chest, E: Tuberculin skin test,  <response>: This is a clinical vignette describing a 3-month-old girl with respiratory distress and a history of hemangiomas being treated with prednisolone. The stem provides key details including fever, tachypnea, hypoxia, oral thrush, crackles on lung exam, leukocytosis, elevated beta-D-glucan, and diffuse interstitial infiltrates on chest x-ray. Based on the history, exam and initial workup, the main diagnostic considerations are an infectious process versus a medication side effect. The oral thrush and elevated beta-D-glucan point towards an invasive fungal infection, likely candida, as the girl is on immunosuppressive therapy with prednisolone. Of the answer choices provided, bronchoalveolar lavage would allow sampling of the lower respiratory tract to confirm the presence of candida infection through culture or stains. The other tests are less likely to provide a definitive diagnosis.A: Bronchoalveolar lavage 