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
Leucovorin rescue is related to : 
Select and explain. 
A. Methotrexate toxicity, B. Cyclophosphamide toxicity, C. Oncovin toxicity, D. Cisplatin toxicity
A: Methotrexate toxicity
Answer: A: Methotrexate toxicity 
Explanation: None