Which statement below is true about how the functions of the digestive and circulatory system are connected.

a
The digestive system moves molecules from the villi to the cells and the circulatory system breaks down food molecules
b
The digestive system breaks down the food into molecules that can be used by the cells. The circulatory system moves the molecules from the villi to all the cells in the body.
c
The digestive system sends messages to the brain and the circulatory system breaks down food molecules
d
all of the above are true