What Theory of Mercury's Origin Can Best Explain the Fact

Multiple Choice

What theory of Mercury's origin can best explain the fact that its core is made of such dense materials?

A) Mercury was formed in the outer solar system and later wound up in its present orbit
B) giant impacts in its early history may have torn away much of its original crust and mantle
C) giant impacts early in its history added a tremendous amount of material to the original planet
D) a large satellite (made of the same material as the Earth's Moon) crashed into Mercury early in its history
E) Mercury was briefly inside the Sun, and thus lost much of its earliest material