The correct answer is A. be protected.

An emergency power-off switch is an important safety control, but it can also create a serious availability risk if activated accidentally or maliciously. Therefore, it should be clearly identifiable to authorized personnel but physically protected from accidental activation. Protection may include a cover, guard, alarm, restricted access, or placement that prevents accidental contact while still allowing emergency use.

Option B is not the best answer because remote accessibility may increase the risk of unauthorized or accidental shutdown. Option C is usually not practical in an emergency, because requiring dual control could delay urgent action. Option D is incorrect because emergency controls must be identifiable during a crisis. The key is that they should be identified but protected.

This maps mainly to Protection of Information Assets because physical and environmental controls support the confidentiality, integrity, and availability of information processing facilities. ISACA’s CISA Exam Content Outline includes physical and environmental security controls under protection-related knowledge areas.