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: Pathology
[{'content': 'In an adult man, there is about how much grams of hemoglobin in the circulating blood? \nSelect and explain. \nA. 350, B. 500, C. 900, D. 1000', 'role': 'user'}, {'content': 'Answer: C \nExplanation: About 900g\xa0of hemoglobin is present in the circulating blood of an adult man.\nAlso know:\n\nThe erythrocytes carry hemoglobin in the circulation. They are biconcave disks because of the protein called as spectrin.\nIn humans, the RBCs survive in the circulation for an average of 120 days.\nThe average normal red blood cell count is 5.4 million/ L in men and 4.8 million/ L in women.\n1g of hemoglobin yields 35mg of bilirubin.', 'role': 'assistant'}]