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': 'Intron is not found in which DNA: \nSelect and explain. \nA. Nuclear DNA, B. Mitochondrial DNA, C. B DNA, D. Z DNA', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mitochondrial DNA', 'role': 'assistant'}]