<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 27-year-old man comes to the physician because of a 4-month history of unintentional weight gain, fatigue, and decreased sexual desire. There is no personal or family history of serious illness. His blood pressure is 14988 mm Hg. Physical examination shows central obesity and abdominal striae. He has a prominent soft tissue bulge at the dorsum of his neck. Laboratory studies show a 24-hour urinary free cortisol of 200 μg N 50 and a morning serum ACTH of 1 pgmL N 750. Which of the following tests is most likely to confirm the underlying etiology of this patients symptoms?? A: CRH stimulation test, B: ACTH stimulation test, C: Chest CT, D: Abdominal CT, E: Brain MRI,  <response>: This is a clinical case about a 27-year-old man with symptoms of weight gain, fatigue, decreased libido, high blood pressure, central obesity, abdominal striae, and a neck mass, along with lab findings of elevated 24-hour urinary free cortisol and low morning ACTH. The key findings are signs and symptoms of hypercortisolism Cushings syndrome along with lab evidence of elevated cortisol and suppressed ACTH. This indicates an ACTH-independent cause of Cushings, like an adrenal tumor. The question asks which test is most likely to confirm the underlying etiology. A CRH stimulation test assesses the pituitary-adrenal axis response and would not be helpful in ACTH-independent Cushings. ACTH stimulation test also assesses adrenal response to ACTH and is not useful here. CT of the chest or abdomen can identify an adrenal tumor causing cortisol excess. Brain MRI would not be helpful.Therefore, the test most likely to confirm the cause in this patient is an abdominal CT to look for an adrenal tumor.D: Abdominal CT 