Which of the Following Is a Feature of Vitamin D

Which of the following is a feature of vitamin D nutrition in the elderly?

A) Most elderly receive near-RDA amounts of the vitamin
B) Aging reduces the kidneys' ability to convert vitamin D to its active form
C) The RDA for vitamin D in the elderly is lower due to less excretion by the kidneys
D) Most elderly rely primarily on self-synthesis of the vitamin due to their greater time spent outdoors