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': 'In presence of Halden effect, CO2 uptake is 2 ml/ 100 ml of blood in aeries, what will be CO2 uptake in absence of Haldone effect in veins ? \nSelect and explain. \nA. 2 ml/100 ml of blood, B. 4 ml/100 ml of blood, C. 6 ml/100 ml of blood, D. 8 ml/100 ml of blood', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 4 ml/100 ml of blood", 'role': 'assistant'}]