The Nurse Is Instructing a Mother to Encourage Her School-Age

The nurse is instructing a mother to encourage her school-age children to play out of doors because it will help reduce the risk of osteomalacia by:

A) Increasing renal perfusion, which helps to activate vitamin D.
B) Increasing the level of an inactive form of vitamin D in the blood.
C) Increasing osteoblastic activity to maintain calcium in the bone.
D) Enhancing activation of the parathyroid hormone.