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: Surgery
[{'content': 'Which of the following is the first sign that appear in hemorrhagic shock? \nSelect and explain. \nA. Hypotension, B. Tachycardia, C. Hypertension, D. Syncope', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]