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': 'Central cyanosis not occurs when total Hb and reduced Hb level is respectively (in gmdeg/o): \nSelect and explain. \nA. 10.9 & 4.1, B. 10.9 & 5.110.9 & 6.1, C. 8.9 & 4.1, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. 10.9 & 4.1', 'role': 'assistant'}]