Two Planes of a Crystal Are Separated by 3 $\times$ 10^-10 M)

Multiple Choice

Two planes of a crystal are separated by 3.25 Angstroms (or 3.25 $\times$ 10^-10 m) . Light of what wavelength shows constructive interference at a scattering angle of 17.5 degrees?

A) 3.9 Angstroms
B) 0.49 Angstroms
C) 9.75 Angstroms
D) 1.46 Angstroms
E) 1.95 Angstroms