An elderly patient has reduced mobility in his lower extremities.It has been observed that there are dark areas under the skin where blood has pooled.This pooling is most likely caused by

A)a decrease in muscle contraction in the arterioles.
B)a decrease in the surface area of the capillaries.
C)an increase in peripheral resistance.
D)a reduction in blood flow through the veins.
E)an increase in production of endothelin in blood vessels.