This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluids and Electrolyte Imbalance, Subject name: Medicine
[{'content': 'Calculate the anion gap from the following information: Na+ = 137mmol/L K+ = 4 mmol/L Cl- = 110 mmol/L HCO3 = 15 mmol/L \nSelect and explain. \nA. 22 mmol/L, B. 16 mmol/L, C. 10 mmol/L, D. 12 mmol/L', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Formula: (Blood) Anion gap - Normal 6-12 mmol/L = - (K+ value not taken in consideration) =137- = 137-12 =12 Urinary anion gap = - | (HCO3-not considered) Normal=0 , As urine is electroneutral', 'role': 'assistant'}]