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': 'The pheonomenon of "sparing off the macula" is due to the collateral circulation between - \nSelect and explain. \nA. Middle and posterior cerebral arteries, B. Anterior and middle cerebral arteries, C. Anterior and posterior cerebral arteries, D. Anterior, middle and posterior cerebral artries', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]