This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cytotoxic Anticancer Drugs, Subject name: Pharmacology
[{'content': 'Maintenance of high urinary pH is impoant during methotrexate treatment because: \nSelect and explain. \nA. Bladder irritation is reduced, B. It decreases renal tubular secretion of methotrexate, C. Leucovorin toxicity is increased in a dehydrated patient, D. Methotrexate is a weak acid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Methotrexate is a weak acid and is reabsorbed in acidic urinary pH. Higher plasma concentration may result in toxicity. Therefore, to decrease the reabsorption through renal tubules, high urinary pH must be maintained.', 'role': 'assistant'}]