You are answering a USMLE-style medical question. Question: A 55-year-old woman is found to have an abnormal mass on routine mammography. The mass is biopsied and cytology results are diagnostic for invasive ductal adenocarcinoma that is estrogen receptor positive. The patient is started on chemotherapy and ultimately has the mass resected. She is taking tamoxifen and has regular outpatient follow up appointments to monitor for any recurrence of cancer. The patient has a past medical history of asthma, obesity, and a uterine leimyoma which was definitively treated last year. Her last menstrual period was at the age of 47. The patient's vital signs and exam are unremarkable. Which of the following is a potential complication that could occur in this patient? Options: A) Deep venous thrombosis B) Eruption of seborrheic keratoses C) Increased bleeding D) Osteoporosis Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.