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
The 5α reductase inhibitor that has been found to be effective both in benign prostatic hypertrophy and male pattern baldness is: 
Select and explain. 
A. Flutamide, B. Finasteride, C. Prazosin, D. Minoxidil
B: Finasteride
Answer: B: Finasteride 
Explanation: None