Which of the following is a technical or administrative control for securing computer systems and communication networks?

• A. Installing network security defenses
• B. All of the above
• C. Encrypting sensitive data files
• D. Installing operating system security

Answer: (B)

Technical controls are the concrete protections built into technology to guard computer systems and networks. In this item, each option describes a direct technical control: installing network security defenses such as firewalls or intrusion prevention systems protects the network at the boundary and monitors traffic; encrypting sensitive data files safeguards information by making it unreadable without the proper keys; installing operating system security involves configuring and enforcing protections at the OS level, including patch management and access controls. Since all of these are examples of technical controls, selecting all of the above is the best choice. Administrative controls, while important, refer to policies, procedures, and training rather than technical mechanisms, and they’re not what these options describe.