Answer: X rays have a short wavelength.
Explanation :
The wavelength of the x rays is, λ₁ = 0.01 nm to 10 nm
The wavelength of the visible light is, λ₂ = 380 nm to 750 nm
The frequency is inversely proportional to the wavelength of light i.e.
So, the high-frequency x-rays have a short wavelength as compared to visible light.
Hence, the correct option is (d) " short ".