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': 'Which of following is not absorbed in PCT: \nSelect and explain. \nA. Bicarbonate, B. Sodium, C. Phosphate, D. H+', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. H+', 'role': 'assistant'}]