The human body needs a specific level of calcium in the blood to maintain internal stability. The feedback loop below shows how the body responds to a decrease in the blood calcium level. feedback loop showing the regulation of blood calcium levels

As shown in the feedback loop, the intestines need vitamin D to absorb calcium. However, a person may have a low level of vitamin D because of their diet. How would a low level of vitamin D affect the body's response to a decrease in the blood calcium level?
A.
It would decrease the amount of calcium absorbed by the kidneys so the blood calcium level could remain low.
B.
It would cause more calcium to be absorbed by the intestines to return the blood calcium level to normal.
C.
It would prevent any calcium from entering the bloodstream so the blood calcium level could remain low.
D.
It would cause more calcium to be released from bones to return the blood calcium level to normal.