At Their Centers, All the Jovian Planets Have Cores Made

At their centers, all the jovian planets have cores made of:

A) hydrogen and helium in the form of gas
B) hydrogen and helium in the form of liquids
C) methane, ammonia, and sulfur compounds
D) a solid mixture of rocky and icy materials under great pressure
E) new elements produced by the high pressure; elements which we do not have on Earth