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': 'Blood for acid base gas (ABGO analysis in a bottle containing heparin can cause decreased value of - \nSelect and explain. \nA. pCO2, B. HCO2, C. pH, D. pO2', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]