This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
Aromatase inhibitors in Ca breast 
Select and explain. 
A. Letrozole, B. Anastrozole, C. Exemestane, D. Tamoxifen
A: Letrozole
Answer: A: Letrozole 
Explanation: letrozole is nonsteroidal competitive inhibitor of enzyme aromatase this enzyme conves adrenal androgen to oestrogens it is used an adjuvant endocrine therapy in post menopausal women with hormone sensitive breast carcinoma ref ;(page no;551) 5th edition of SRB&;S Manual of SURGERY