This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid and electrolytes, Subject name: Medicine
[{'content': 'Persistant vomiting most likely causes- \nSelect and explain. \nA. Hyperkalemia, B. Acidic urine excretion, C. Hypochloraemia, D. Hyperventilation.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Metabolic alkalosis occurs as a result of loss of nonvolatile acid HCl while vomiting( from the extracellular fluid. ', 'role': 'assistant'}]