This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2017, Subject name: Physiology
[{'content': 'A patient presents with right to left shunt. Oxygen content in aerial and venous side are 18 and 14 ml/100 ml respectively. Oxygen content at pulmonary capillary is 20. What is the percentage shunting of cardiac output? \nSelect and explain. \nA. 23%, B. 33%, C. 43%, D. 53%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Normal O2 content Aerial - 20ml Venous - 14 ml Aeriovenous difference - 6 ml In the given condition, O2 content Aerial - 18 ml Venous - 14 ml Aeriovenous difference - 4 ml i.e. 1/3 of the normal is reduced in the given shunting. So, there will be a reduction of 33% or 2 ml', 'role': 'assistant'}]