In a Particular Form of Silicon, the Atoms Are Arranged

In a particular form of Silicon, the atoms are arranged in a rectangular grid of spacing 2x10-10 m. Each atom weighs 4.7x10-26 kg. What is the density of this form of Silicon, in g cm-3?

A) 0.32 g cm-3.
B) 1.3 g cm-3.
C) 3.3 g cm-3.
D) 5.8 g cm-3.
E) 33.2 g cm-3.