Which of the following best describe the more expensive UPS devices? (Choose all that apply)

A.
These kinds of UPS add filters to smooth any power spikes and to boost low voltages.

B.
These kinds of UPS are recommended for server farms.

C.
These kinds of UPS are used for large network systems that support enterprise networking environments.

D.
These kinds of UPS are recommended for Internet Service Providers (ISPs).

Explanation:
More expensive UPS devices are called online interactives, which provide some power conditioning along with battery backup. They add filters to smooth any power spikes and to boost low voltages. They are always recommended for mission-critical applications such as server farms, Application Service Providers (ASPs), Internet Service Providers (ISPs), telecommunications facilities, manufacturing plants, and medical operations, and they offer the highest level of server power protection available.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 227-240.