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
Deficiency of vasopressin results in: 
Select and explain. 
A. Inability of the kidney to concentrating urine, B. Increased Na+ loss, C. Hyperkalemia, D. Decreased urine output
A: Inability of the kidney to concentrating urine
Answer: A: Inability of the kidney to concentrating urine 
Explanation: Inability of the kidney to concentrating urine