The correct answer is C. Be protected.
An emergency power-off switch is a critical safety mechanism, but it also creates operational risk if it can be triggered accidentally or without proper safeguards. ISACA's official CISA practice material specifically treats a missing cover on an emergency power-off button as a significant concern, which supports the conclusion that the switch should be protected against accidental activation.
Option A is incorrect because remote accessibility could increase the risk of misuse or accidental shutdown.
Option B is incorrect because the switch should be identifiable in an emergency; hiding it would conflict with emergency response needs.
Option D is incorrect because dual control is not the primary requirement for an emergency switch intended for urgent use.
Therefore, the correct answer is C, because the switch should be protected, typically by a cover or similar safeguard, while still remaining available for emergency use.
References (Official ISACA):
ISACA, CISA Practice Quiz - identifies a missing emergency power-off button cover as a significant concern.