This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteoporosis, Sex Hormones and OCPs, Subject name: Pharmacology
[{'content': 'Dr. Shweta decided to add a progestin for 10-12 days each month to estrogen replacement therapy in menopausal women in the gynaecology OPD. Addition of progestin is recommended because the progestin: \nSelect and explain. \nA. Blocks the increased risk of myocardial infarction due to estrogen, B. Blocks the increased risk of endometrial carcinoma due to estrogen, C. Reverses vulval atrophy occurring in post menopausal women, D. Enhances the metabolic benefits of estrogen treatment', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Use of estrogen for the treatment or prevention of post-menopausal osteoporosis --> increase risk of breast and endometrial carcinoma. Progesterone is used to decrease the risk of endometrial carcinoma.', 'role': 'assistant'}]