Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: The syndrome of inadequate secretion of antidiuretic hormone (SIADH) is characterized by: 
 Options:  <1> Hyponatremia <2> Hypovolemia <3> Concentrations of sodium ion in urine less than 20 mmol / L. <4> Osmolality in urine less than serum osmolality. <5> High concentrations of calcium ion.
