Which Statement About Vitamin D Is CORRECT

Which statement about vitamin D is CORRECT?

A) Vitamin D induces the synthesis of proteins needed for the active transport of calcium across the intestine.
B) Vitamin D induces the synthesis of proteins needed for the passive transport of calcium across the intestine.
C) Vitamin D is most necessary when calcium intake is high.
D) Adequate consumption of vitamin D increases the absorption of calcium to 50%.