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  a  healthy  individual  on  a  normal  diet,  which of  the  following  ion is  completely  absorbed  in  tubules? \nSelect and explain. \nA. Na +, B. K, C. Cl –, D. HCO3 –', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]