When anatomists use directional terms, which of these is NOT a consideration?

A) The position of a body part is described relative to another body part.
B) Structures such as blood vessels can be described relative to an origin, the heart, using the terms proximal or distal.
C) Humans stand upright, so terms such as anterior and ventral (or posterior and dorsal, or superior and cephalic) are interchangeable; this is not true for four-legged animals.
D) Structures on the limbs are usually described as proximal or distal.
E) The directional terms are used with the assumption that the body is in a supine position with the hands facing palm upward.