This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'On increasing vagal tone following occurs in pacemaker \nSelect and explain. \nA. Increased K+ increased slop, B. Decreased K+ decreased slop, C. Increased K+ decreased slop, D. Decreased K+ increased slop', 'role': 'user'}, {'content': "Answer: B \nExplanation: When the cholinergic vagal fibers to nodal tissue are stimulated, the membrane becomes hyperpolarizedThe slope of the prepotentials is decreased because the acetylcholine released at the nerve endings increases the K+ conductance of nodal tissue.Which cause rapid efflux of K+Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No: 491", 'role': 'assistant'}]