One of the Solid Forms of Iron, Called $\alpha$ -Iron, Crystallizes in a Body-Centered Cubic Lattice

Multiple Choice

One of the solid forms of iron, called $\alpha$ -iron, crystallizes in a body-centered cubic lattice. If atomic planes of this form of iron are separated by 143.3 pm, at what angle would you find the first-order (n = 1) diffraction of 0.209 nm X-rays from these planes?

A) 43.2°
B) 21.4°
C) 23.4°
D) 0.817°
E) 46.8°