Organizations can manage the security of large networks by dividing them into separate network domains and separating them from the public network where appropriate. This reflects the principle of network segregation, which reduces the ability of an attacker, malware, or unauthorized user to move freely across the environment. Separate domains can be based on trust level, business function, system criticality, data sensitivity, user group, supplier access, development environment, or regulatory requirement. ISO/IEC 27002 supports this through network security, network segregation, access control, and secure architecture practices.
Option B is incorrect because including internal domains into the public network would increase exposure and weaken boundaries. Option C is not realistic or aligned with modern enterprise architecture; organizations often need integrated services, users, and systems, but they must integrate them securely. Segmentation allows controlled communication through firewalls, gateways, routing rules, access controls, monitoring, and filtering. The goal is not isolation for its own sake, but risk-based separation and controlled connectivity.
Therefore, option A is verified. References/Chapters: ISO/IEC 27002:2022, Control 8.20 Network security; Control 8.22 Segregation of networks; Control 5.15 Access control.

Control 6.1 Screening is the ISO/IEC 27002 control that helps organizations ensure employees and contractors are suitable for their roles. Screening is performed before employment or engagement, and it should be proportionate to business requirements, information classification, access levels, legal requirements, and the risks associated with the role. It may include verification of identity, qualifications, employment history, references, criminal record checks where lawful and appropriate, and professional credentials. The goal is not unnecessary intrusion; the goal is to reduce the risk that unsuitable individuals receive access to sensitive information, systems, facilities, or responsibilities. Control 6.4, Disciplinary process, deals with responding to policy violations after employment has begun. Control 6.7, Remote working, addresses security arrangements for work outside organizational premises. Neither directly verifies suitability before assigning a role. ISO/IEC 27002 treats people controls as essential because insider risk, negligence, excessive access, and role mismatch can create significant security exposure. Therefore, option A is the verified answer. References
/Chapters: ISO/IEC 27002:2022, Control 6.1 Screening; Control 6.2 Terms and conditions of employment; Control 6.3 Information security awareness, education and training.

ISO/IEC 27002 requires equipment to be sited and protected in a way that reduces risks from physical and environmental threats. These threats include fire, flood, dust, vibration, electrical interference, unauthorized access, power instability, temperature extremes, and other environmental hazards. Option A is correct because secure siting and protection of equipment are essential to preserving confidentiality, integrity, and availability of information processing facilities. Option B is incorrect because equipment can absolutely be affected by power failures, utility disruptions, voltage fluctuations, overheating, and related events. Option C is incorrect because supporting utilities should be maintained, monitored, and tested as appropriate over time, not only at the beginning. ISO/IEC 27002 physical controls emphasize that technical systems depend on the physical environment. Servers, network devices, storage, and endpoint systems need appropriate location, power, cooling, cabling protection, and resilience measures. Equipment placement should also reduce unauthorized viewing, tampering, theft, and environmental exposure. The verified answer is option A because it reflects the physical protection objective in ISO/IEC 27002. References/Chapters: ISO/IEC 27002:2022, Control 7.8 Equipment siting and protection; Control 7.5 Protecting against physical and environmental threats; Control
7.11 Supporting utilities.

Labelling procedures help communicate information classification levels to people and systems, supporting proper handling.