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 electrocardiographic findings may represent manifestations of digitalis intoxication, EXCEPT - \nSelect and explain. \nA. Bigeminy, B. Junctional tachycardia, C. Atrial flutter, D. Atrial tachycardia with variable block', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]