This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
Which of the following is an indication for the use of folinic acid? 
Select and explain. 
A. Prophylaxis of neural tube defects in the offspring of women receiving anticonvulsant medications, B. Counteracting toxicity of high dose methotrexate therapy, C. Pernicious anemia, D. Anemia associated with renal failure
B: Counteracting toxicity of high dose methotrexate therapy
Answer: B: Counteracting toxicity of high dose methotrexate therapy 
Explanation: Prophylaxis of neural tube defects require treatment with folic acid. Methotrexate toxicity can be prevented by 5'-formyltetrahydrofolate (folinic acid). Pernicious anemia requires the therapy with vitamin B12. Anemia associated with chronic renal failure is treated with erythropoietin.