What is a benefit of having an Uninterruptible Power Supply (UPS) attached to a server?

What is a benefit of having an Uninterruptible Power Supply (UPS) attached to a server?
A . Provides permanent power to a server, eliminating the need for a wall outlet.
B . Replaces the need for power supplies in a server.
C . Keeps a server running during a long power outage
D . Provides short-term protection to allow a server to be shut down gracefully.

Answer: D