This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
[{'content': 'Which one of the following is the best stimulus for the release of the Arginine-vasopressin? \nSelect and explain. \nA. Hypertonicity, B. Hypokalemia, C. Intravascular volume depletion, D. Hypernatremia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Hypertonicity', 'role': 'assistant'}]