A 62-year-old postmenopausal woman with a T-score of −3.2 at the femoral neck presents for osteoporosis management. She has no renal impairment and normal serum calcium. The physician explains that the pathway marked **C** in the diagram (RANKL → RANK signaling) is the key mechanism driving her bone loss. To inhibit this pathway and reduce fracture risk, which of the following agents would be most appropriate for this patient?