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: Pharmacology
[{'content': 'Dobutamine increases: \nSelect and explain. \nA. Heart rate, B. Cardiac output, C. Blood pressure, D. Plasma volume', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]