Which three elements are commonly cited as the core types of security?

• A. Network, System, Data
• B. People, Policies, Procedures
• C. Firewall, Antivirus, IDS
• D. Hardware, Software, Users

Answer: (A)

Focusing on where protections are applied helps organize security in a practical way: across the network, on the systems themselves, and around the data those systems handle. Network security protects communications and infrastructure from unauthorized access and threats as data travels and sits on networks. System security hardens the devices and environments themselves—servers, workstations, and endpoints—through proper configurations, patching, access controls, and secure management. Data security centers on the information itself—encryption, integrity checks, access restrictions, and secure handling to keep data confidential and trustworthy. Together, these three domains create a layered, defense-in-depth approach that covers the main areas where security controls are implemented.

The other options touch important aspects of security but not the broad categories described above. People, policies, and procedures relate to governance and human factors rather than the primary security domains. Tools like a firewall, antivirus, and IDS are specific controls, not overarching domains. Hardware, software, and users describe components of an IT environment rather than the domains where security is systematically applied.