Cesium Iodide Consists of a Simple Cubic Lattice of L^-

Cesium iodide consists of a simple cubic lattice of l^- ions with Cs⁺ ions in the center of the cubes. If the cell edge length is 0.445 nm, what is the Cs-I interatomic distance in nanometers?

A) 0.193 nm
B) 0.314 nm
C) 0.385 nm
D) 0.629 nm
E) 0.770 nm