D. It detects light waves that are able to pass through an object.
X-rays are a form of electromagnetic radiation, similar to light waves but with a higher frequency and energy. X-ray machines work by generating a beam of X-rays that pass through the body and are detected on the other side by a specialized X-ray detector. The X-rays that pass through the body are attenuated (absorbed) to varying degrees by different tissues and structures, depending on their density and atomic composition. This results in a shadow-like image on the detector, with denser structures appearing as lighter areas and less dense structures appearing as darker areas. X-ray machines are commonly used in medicine to diagnose a variety of conditions and injuries, as well as in other fields such as materials science and airport security.