<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 23-year-old male presents with complaints of polydipsia and frequent, large-volume urination. Laboratory testing does not demonstrate any evidence of diabetes; however, a reduced urine osmolality of 120 mOsmL is measured. Which of the following findings on a desmopressin test would be most consistent with a diagnosis of central diabetes insipidus?? A: Reduction in urine osmolality to 60 mOsmL following vasopressin administration, B: Reduction in urine osmolality to 110 mOsmL following vasopressin administration, C: Increase in urine osmolality to 130 mOsmL following vasopressin administration, D: Increase in urine osmolality to 400 mOsmL following vasopressin administration, E: No detectable change in urine osmolality following vasopressin administration,  <response>: This is a clinical vignette describing a patient with symptoms and lab findings consistent with diabetes insipidus. The question is asking which finding on a desmopressin test would confirm a diagnosis of central diabetes insipidus. In central diabetes insipidus, there is insufficient secretion of vasopressin antidiuretic hormone from the posterior pituitary. This leads to the production of dilute urine with low osmolality. Administering exogenous vasopressin should correct the urine concentration defect in central diabetes insipidus. Choices A and B show a further reduction in urine osmolality after desmopressin, which would not be expected. Choice C shows only a mild increase, which is inadequate. Choice E shows no response, which may indicate nephrogenic diabetes insipidus where the kidneys are unable to respond to vasopressin. Choice D shows the expected marked increase in urine osmolality after desmopressin administration, consistent with central diabetes insipidus.D: Increase in urine osmolality to 400 mOsmL following vasopressin administration 