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': 'Finasteride acts by blocking: \nSelect and explain. \nA. α-receptors, B. 5–α reductase enzyme, C. Androgen receptors, D. β–receptors', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]