The answer is b.
The patient suffers from osteomalacia, a disease related to malnutrition, specifically vitamin D deficiency. On the basis of the first bone biopsy in which the tissue was decalcified, one could make a diagnosis of osteoporosis. The second, nonde- calcified bone biopsy indicates that osteoid is being formed but is not undergoing mineralization. This correlates with the low 25-hydroxyvitamin D levels. Vitamin D replacement and calcium supplementation would be prescribed for this patient.