The Density of Mercury Is About the Same as That

The density of Mercury is about the same as that of Earth,but Mercury contains a larger proportion of iron.How is this possible?

A) The iron in Mercury's core is accompanied by a very low-density crust. The average density is thus comparable to the density of Earth.
B) The inner core of Mercury is hollow, thus reducing the overall density much below that of iron.
C) Mercury has only 1/18 Earth's mass. Thus, it must be composed of heavier materials (like iron) in order to match Earth's density.
D) The Earth contains, proportionally, a smaller volume of iron, but because of Earth's greater mass, Earth's iron has been compressed to a higher density than the iron on Mercury.