Answer:
D. Ultraviolet disinfecting wand.
Step-by-step explanation:
Energy in light waves depends upon the frequency o the waves. Higher the frequency of the waves, higher the amount of energy it carries. Similarly, waves with shorter wavelength has higher frequencies and thus more energy.
Ultraviolet disinfecting wand would produce most energy out of the four options because it produce UV waves which have shorter wavelength and higher frequency.