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
Which of the following is an aromatase inhibitor ? 
Select and explain. 
A. Tamoxifen, B. Letrozole, C. Danazol, D. Taxane
B: Letrozole
Answer: B: Letrozole 
Explanation: None