The Four Galilean Satellites of Jupiter Do Not All Have

The four Galilean satellites of Jupiter do not all have the same mean density because:

A) heat from Jupiter prevented ice from forming at the locations of the inner satellites.
B) heat from the Sun prevented ice from forming in the outer part of the "jovian nebula," from which the satellites formed.
C) the larger satellites are more gravitationally compressed.
D) the satellites formed at different distances from the Sun and were later captured by Jupiter.