increase in osteocyte activity

12. Osteoporosis result from which of the followings?

a. A decline of osteoblast activity while osteoclast activity continues at expected levels
b. A decline of osteoclast activity while osteoblast activity continues at expected levels
c. An increase in osteocyte activity while osteoblast activity continues at expected levels
d. An increase in osteocyte activity while osteoclast activity continues at expected levels