Which of the following statements regarding moving stairs is MOST accurate?

A) Typically, vertical openings created by escalators need to be protected when serving more than three floors.
B) Vertical openings can be protected by a rolling shutter at the bottom of the escalator.
C) The most common method of protecting the vertical opening created by an escalator is using closely spaced sprinklers in conjunction with draft stops.
D) A partial enclosure uses a single fire-rated enclosure for both the up and down escalator.

C