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
[{'content': 'The first physiological response to high environmental temperature is: \nSelect and explain. \nA. Sweating, B. Vasodilatation, C. Decrease heat production, D. Non-shivering thermogenesis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]