If your instructor asked you to compare the structure of the upper and lower extremities, vich of the following might you say?

a$.$ There are no similarities in the structures of the upper and lower extremities.

b$.$ Both the upper and lower extremities are divided into two regions.

c$.$ The upper and lower extremities have a similar structure, with a large bone articulating with two smaller bones via a joint.

d$.$ Both the upper and lower extremities are divided into four regions.