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': 'Urinary anion gap is? \nSelect and explain. \nA. Plus 1, B. 0, C. Minus 1, D. Cannot be calculated', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Urinary anion gap (Na+ + K+ ) - (Cl- ) = 0 Urine is electro neutral *Anion gap in Blood = (Na+) - (Cl- + HCO3-)', 'role': 'assistant'}]