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 is a side effect of which of the following drug: 
Select and explain. 
A. Methotrexate, B. D-Penicillamine, C. Lefluonamide, D. Hydroxychloroquine
A: Methotrexate
Answer: A: Methotrexate 
Explanation: Methotrexate