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: Physiology
The most common electrolyte disorder encountered in clinical practice 
Select and explain. 
A. Hyponatremia, B. Hypocalcemia, C. Hypernatremia, D. Hypokalemia
A: Hyponatremia
Answer: A: Hyponatremia 
Explanation: Hyponatremia is the most common electrolyte disorder encountered in clinical practice and may occur in up to 15% to 25% of hospitalized patients.