<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A young woman from the Ohio River Valley in the United States currently on corticosteroid therapy for ulcerative colitis presented to a clinic complaining of fever, sweat, headache, nonproductive cough, malaise, and general weakness. A chest radiograph revealed patchy pneumonia in the lower lung fields, together with enlarged mediastinal and hilar lymph nodes. Skin changes suggestive of erythema nodosum i.e. an acute erythematous eruption were noted. Because the patient was from a region endemic for fungal infections associated with her symptoms and the patient was in close contact with a person presenting similar symptoms, the attending physician suspected that systemic fungal infection might be responsible for this womans illness. Which of the following laboratory tests can the physician use to ensure early detection of the disease, and also effectively monitor the treatment response?? A: Culture method, B: Antibody testing, C: Fungal staining, D: Antigen detection, E: Skin tests,  <response>: This is a medical question asking about the best laboratory test to detect and monitor a suspected systemic fungal infection in a patient with symptoms like fever, cough, lymph node enlargement, and skin changes. The key points in the question stem are:- Patient is from an area endemic for fungal infections- Has symptoms suggestive of systemic fungal infection - Needs a test for early detection and to monitor treatment responseLooking at the choices:- Culture method A takes time to grow fungi and confirm infection. Not ideal for early detection.- Antibody testing B indicates past exposure. Not useful for early detection of active infection. - Fungal staining C can detect fungi in tissuesfluids but has low sensitivity. Not ideal for monitoring.- Antigen detection D can identify fungal proteins and diagnose active infection early. Can also be used serially to monitor treatment. - Skin tests E assess delayed hypersensitivity reaction. Not useful for diagnosis or monitoring treatment response.D: Antigen detection 