The doors of a data center opens up in the event of a fire. This is an example of

A.
Fail-safe

B.
Fail-secure

C.
Fail-open

D.
Fail-closed

Explanation:
A: Fail-safe mechanisms focuses on failing with a minimum of harm to personnel while fail-secure focuses on failing in a controlled manner to block access while the systems is in an inconsistent state. For example, data center door systems will fail safe to ensure that personnel can escape the area when the electrical power fails. A fail-secure door would prevent personnel from using the door at all, which could put personnel in jeopardy. Fail-open and fail-closed are fail safe mechanisms. Page 545.