If Venous Pressures in the Venules Range from 17-21 Mm

If venous pressures in the venules range from 17-21 mm Hg and pressures in the venae cavae range from 2-4 mm Hg, what is the pressure range of the driving force pushing blood through the venous system?

A) 2-4 mm Hg
B) 13-19 mm Hg
C) 15-17 mm Hg
D) 19-25 mm Hg
E) 21-23 mm Hg