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 main cause of increased blood flow to exercising muscles is : \nSelect and explain. \nA. Raised blood pressure, B. Vasodilatation due to local metabolites, C. Increased sympathetic discharge to peripheral vessels, D. Increased hea rate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Vasodilatation due to local metabolites', 'role': 'assistant'}]