What term describes one or more characters following the last period in a filename, such as .exe, .txt, or .avi?

In Linux, everything—including all devices, partitions, and folders—is seen as a unified ________

Fill in the blank(s) with correct word

_______ should be located on the floor of computer rooms as well as under raised floors, and should cut off power automatically in the event of a flood.

A. Smoke detectors B. UPS C. Water sensors D. Equipment power off switches