How Do Respiratory Movements and Skeletal Muscle Contraction Affect Circulation

How do respiratory movements and skeletal muscle contraction affect circulation?

A) They are synergistic because both assist circulation by squeezing and "pumping" venous blood.
B) They are antagonistic forces because skeletal muscles assist venous blood movement, but respiratory activity inhibits venous movement.
C) Both synergistically lower blood pressure by enhancing vasodilation, which directly stimulates the cardiac regulatory center.
D) Both synergistically increase blood pressure by stimulating the sympathetic nervous system to vasodilate arteries.