A 65-year-old woman is noted to have suspected uterine fibroids on physical examination. Over the course of 1 year, she is noted to have enlargement of her uterus from approximately 12 weeks’ size to 20 weeks’ size. Which of the following is the best management? () A: Continued careful observation B: Monitoring with ultrasound examinations C: Exploratory laparotomy with hysterectomy D: Gonadotropin-releasing hormone agonist E: Progestin therapy