Compared to gamma rays, x–rays have relatively

less energy and short wavelengths.

more energy and short wavelengths.

less energy and long wavelengths.

more energy and long wavelengths.

Gamma rays are known to have the greatest frequency and the shortest wavelength. What we also know is that frequency and energy are directly proportional (they are the same), and that the wavelength is the opposite of them - if frequency/energy are high, the wavelength will be short, and vice versa.
Since X-rays are the opposite of gamma rays, then the correct answer is the third option - less energy and long wavelengths.

Lexy is correct because angle r is between the incident wave,  n  = 0, and a diffracted wave.