Why Would Exercise Help Your Blood Circulation in Your Legs

Why would exercise help your blood circulation in your legs?

A) As muscles contract they squeeze blood through the veins and increased heart rate pushes more blood into the legs.
B) Increased heart rate pushes more blood into the legs only.
C) As muscles contract they squeeze blood through the veins only.
D) Exercise increases the amount of red blood cells only.
E) Exercise increases the amount of red blood cells and increased heart rate pushes more blood into the legs.