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
Oligospermia caused by aEUR' 
Select and explain. 
A. Methotrexate, B. Hydroxychloroquine, C. Leflunomide, D. D-peniollamine
A: Methotrexate
Answer: A: Methotrexate 
Explanation: Methotrexate "Transient but reversible oligospermia has been repoed in males receiving high dose methotrexate for cancer chemotherapy". Defective oogenesis or spermatogenesis "Occurs in methotrexate therapy"