A 54-Year-Old Man with a Lung Tumor Has High Circulating $260 \mathrm{mOsm} / \mathrm{L}$

Multiple Choice

A 54-year-old man with a lung tumor has high circulating levels of antidiuretic hormone (ADH) , a serum osmolarity of $260 \mathrm{mOsm} / \mathrm{L}$ , and a negative free-water clearance $\left(\mathrm{C}_{\mathrm{H}_{2} \mathrm{O}}\right)$ . Which diagnosis is correct?

A) Primary polydipsia
B) Central diabetes insipidus
C) Nephrogenic diabetes insipidus
D) Water deprivation
E) Syndrome of inappropriate antidiuretic hormone (SIADH)