**Core Concept**
Central diabetes insipidus (CDI) is a condition characterized by the inability to produce antidiuretic hormone (ADH), also known as vasopressin, leading to excessive thirst and polyuria. The drug of choice for CDI aims to replace or mimic the action of ADH to regulate water reabsorption in the kidneys.

**Why the Correct Answer is Right**
Desmopressin, a synthetic analogue of vasopressin, is the preferred treatment for CDI. It selectively stimulates the V2 receptors in the collecting ducts of the kidneys, promoting water reabsorption and reducing urine production. This results in decreased thirst and polyuria, improving the symptoms of CDI.

**Why Each Wrong Option is Incorrect**
**Option A:** Vasopressin, while similar to desmopressin, is less selective and can also stimulate V1 receptors, leading to vasoconstriction and potential cardiovascular side effects.
**Option B:** Hydrochlorothiazide, a thiazide diuretic, can be used to treat nephrogenic diabetes insipidus (NDI) but is not effective in central diabetes insipidus as it does not address the underlying issue of ADH deficiency.
**Option C:** Chlorpropamide, an antidiabetic medication, can increase ADH release but is not a first-line treatment for CDI due to its variable efficacy and potential side effects.

**Clinical Pearl / High-Yield Fact**
Desmopressin is often administered intranasally or subcutaneously, and its effects can be monitored by measuring the patient's urine osmolality and 24-hour urine volume.

**Correct Answer: C. Desmopressin**