In Noting That the Earth Is "Differentiated," We Mean That

In noting that the Earth is "differentiated," we mean that

A) the radioactive heating in the core is increasing with time.
B) the Earth's magnetic field varies at different locations on the globe.
C) the Earth is very different than any other planet we study.
D) the density increases as you descend downward toward the core.
E) the density of oceanic basalt is less than that of granite on the mountain tops.