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: Pathology
[{'content': 'In hypovolemic shock: \nSelect and explain. \nA. The central venous pressure is high, B. The extremities are pale, cold and sweating, C. There is always a site of bleeding, D. Urine output is unaffected', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]