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': 'True about anaphylactic shock \nSelect and explain. \nA. Raised PR, B. Peripheral vasoconstriction, C. Raised BP, D. Raised cardiac output', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Due to histamines vasodilation occurs.', 'role': 'assistant'}]