What is the mechanism of action of this drug for this patient?

A 64 year old woman complains of low back pain for 1 week. Her pain and tenderness is localized over the lumbar spine and exaggerated by movement. Her physician prescribes her a phosphonate drug.
What is the mechanism of action of this drug for this patient?

A- Decrease osteoclast activity
B- Increase osteoblast activity
C- Decrease parathormone activity
D- Increase vitamin D absorption
E- Increase urinary calcium reabsorption