Q. A 65-year-old postmenopausal woman presents to the clinic with a history of frequent fractures over the past year. She reports that she has fallen several times and has experienced wrist and hip fractures. Her medical history is significant for hypothyroidism; she is on levothyroxine therapy. She denies any significant family history of osteoporosis or fractures. Physical examination is unremarkable. Diagnostic workup reveals a bone mineral density T-score of -3.0 at the lumbar spine and -2.5 at the femoral neck. Laboratory studies are significant for a serum calcium level of 9.1 mg/dL, serum phosphorus level of 3.3 mg/dL, and serum 25-hydroxyvitamin D level of 20 ng/mL. Which of the following is widely used in the treatment of osteoporosis?