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: Pathology
[{'content': 'In a 32yr old male presenting with the following blood chemistry Na+ → 135,K+ → 5.0, HCO3- → 14.0, Cl- → 116, PO4-- →\n5.0, S04-- → 5.0, Mg++ → 2.0, Ca++→ 8.0 the anion gap is : \nSelect and explain. \nA. 20, B. 15, C. 13, D. 10', 'role': 'user'}, {'content': 'Answer: D \nExplanation: We cannot get the answer by using the calculation we have all been using till now i.e. -\nAnion gap =  - \nthen the anion gap would be - = 5\nBut 5 is not an option\nIn all the books I have looked for i.e., Harrison, Nelson Ganong, Guyton, C.P.D.T., Cecil; anion gap is calculated in\nthe similar way except for Bailey where anion gap is calculated as follows:\nAnion gap =  -  Using this anion gap is\nequal to 140 - 130 = 10', 'role': 'assistant'}]