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
The syndrome of inappropriate and antidiuretic hormone is characterized by the following - 
Select and explain. 
A. Hyponatremia and urine sodium excretion > 20 meq/I, B. Hypernatremia and urine sodium excretion > 20 meq/I, C. Hyponatremia and hyperkalemia, D. Hypernatremia and hypokalemia
A: Hyponatremia and urine sodium excretion > 20 meq/I
Answer: A: Hyponatremia and urine sodium excretion > 20 meq/I 
Explanation: None