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: Pharmacology
[{'content': 'Drug used to counteract Methotrexate toxicity: \nSelect and explain. \nA. Mesna, B. Folinic acid, C. Folic acid, D. Vit B12', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Folinic acid', 'role': 'assistant'}]