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: Medicine
[{'content': 'All of the following are features of Mobiz type I block except - \nSelect and explain. \nA. Constant PR interval, B. Normal QRS morphology, C. Regular atrial rhythm, D. Atrial rate - ventricular rate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]