Niobium Crystallizes in a Body-Centered Cubic Unit Cell

Multiple Choice

Niobium crystallizes in a body-centered cubic unit cell.If the radius of a niobium atom is 0.145 nm,what is the length of an edge of the unit cell?

A) 0.251 nm
B) 0.290 nm
C) 0.335 nm
D) 0.410 nm
E) 0.502 nm