Scenario Blood Flowing Away from the Heart Is Under Tremendous Pressure

Scenario
Blood flowing away from the heart is under tremendous pressure, able to travel to just about any portion of the body. However, blood pressure drops considerably as it moves away from the heart. When blood finally reaches capillaries, the blood pressure drops to nearly zero. Therefore, when a person is standing, blood returning from the feet is not moved back towards the heart by contractions of the heart.
-A scientist claimed that students might get better scores on written exams if they wiggle their legs frequently while taking an exam. This could work (but it is not better than studying) because wiggling legs might ________.

A) propel more blood from the legs back to the heart, increasing oxygen flow to the brain
B) add more oxygen to the blood that is returning to the heart
C) shake out more of the carbon dioxide that lingers in the blood returning to the heart
D) break up blood clots in the legs, which slow the movement of blood back to the heart