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': 'All are effect of parasympathetic system on hea except - \nSelect and explain. \nA. Negative chronotropic, B. Negative ionotrophic, C. Negative dromotropic, D. All are seen', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Negative inotropic", 'role': 'assistant'}]