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': 'Prinzmetal angina has the following characteristics except -a) Pain at restb) ST elevation during the attackc) Normal ECG without paind) Represents transmural ischemiae) ST depression with pain \nSelect and explain. \nA. ce, B. b, C. ac, D. ae', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]