The correct answer is C. laser.
A laser is a beam of light that is produced by a process called stimulated emission. This process occurs when atoms or molecules are excited to a higher energy state by an external source, such as a flash lamp or an electrical discharge. When these atoms or molecules decay back to their ground state, they emit light in a very specific direction and with a very specific wavelength. This light is called laser light.
Laser light is used in a variety of applications, including recording and retrieving data on optical disks. In this application, the laser light is used to create a pattern of pits and bumps on the surface of the disk. This pattern is then read by a laser scanner to retrieve the data.
The other options are incorrect. Polarized light is light that has been aligned in a specific direction. Unpolarized concentric light is light that is emitted in a circular pattern. Colored light is light that has a specific wavelength.