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
Drug useful in breast cancer is : 
Select and explain. 
A. Tamoxifen, B. Cyproterone, C. Testosterone, D. Chlorambucil
A: Tamoxifen
Answer: A: Tamoxifen 
Explanation: None