The purpose of a deadman door controlling access to a computer facility is primarily to:

The purpose of a deadman door controlling access to a computer facility is primarily to:

A.
prevent piggybacking.

B.
prevent toxic gases from entering the data center.

C.
starve a fire of oxygen

D.
prevent an excessively rapid entry to, or exit from, the facility.

Explanation:
The purpose of a deadman door controlling access to a computer facility is primarily intended to prevent piggybacking. Choices B and C could be accomplished with a single self-closing door. Choice D is invalid, as a rapid exit may be necessary in some circumstances, e.g., a fire.