This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'The syndrome of inappropriate antidiuretic hormone is characterized by the following: \nSelect and explain. \nA. Hyponatremia and hyperkalemia, B. Hypernatremia and hypokalemia, C. Hyponatremia and urine sodium excretion >20 meq/1, D. Hypernatremia and urine sodium excretion>20 meq/1', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Syndrome of inappropriate antidiuretic hormone is caused by excess secretion of vasopressin leading to increased absorption of water resulting in hyponatremia, inappropriate sodium secretion in the urine (> 20 mEq/L), hyper osmolar urine (>100mOsm/L) and hypo osmolar plasma (<260mOsm/L). Ref: The MD Anderson Manual of Medical Oncology, 2nd Edition, CHAPTER 46', 'role': 'assistant'}]