Answer the following question given this paragraph: 

Besides entertaining a cat, laser light has many other uses. One use is carrying communication signals in optical fibers. Sounds or pictures are encoded in pulses of laser light, which are then sent through an optical fiber. All of the light reflects off the inside of the fiber, so none of it escapes. As a result, the signal remains strong even over long distances. More than one signal can travel through an optical fiber at the same time, as you can see in the Figure below . Optical fibers are used to carry telephone, cable TV, and Internet signals.


Q: Sounds or pictures can be encoded in pulses of what, which are then sent through an optical fiber?

 Choices:

- kinetic energy

- microwaves

- quasars

- laser light

A:
laser light
