Which type of security is emphasized by Security-Enhanced Linux (SELinux)?

Security-Enhanced Linux (SELinux) primarily emphasizes mandatory access control (MAC). This is a security model that restricts the access rights for users based on the policies set by the system administrator. In contrast to discretionary access control (DAC), where the user has control over their own data and applications, MAC enforces strict policies that determine how processes interact and what resources they can access.

SELinux operates on the principle of least privilege, ensuring that programs and processes operate with only the necessary permissions needed to function, thus reducing the potential impact of vulnerabilities or malicious activity. By implementing these mandatory access control policies, SELinux significantly enhances the security posture of a system, making it more resilient against unauthorized access and exploitation.

The choices referring to network security, physical security, and application security, while important aspects of overall security, do not capture the specific focus of SELinux, which is on restricting resource access through enforced policies rather than on the other aspects mentioned.