Final answer:
The CR reader uses red laser light to release the stored energy in the image plate, emitting it as visible light which is then captured to form an image.
Step-by-step explanation:
The CR reader uses a red laser light to release the energy stored in the image plate. The energy in the photostimulable phosphor plate is stored during exposure to radiation and when the plate is read, the red laser light causes the phosphors to emit the stored energy as visible light. This process is known as photostimulation. The emitted light is then detected and converted into an image that can be viewed and analyzed. Therefore, the correct answer to the question is a. red laser light.