Final answer:
The question is regarding the principle that involves verifying identities in computer systems. The correct answer is the Authentication principle, which is essential for security, and two-factor authentication can strengthen it by combining two different types of credentials.
Step-by-step explanation:
The question appears to be about security principles relevant in the context of computer systems, focusing specifically on user identification and access controls. The correct answer would be option a) Authentication principle. Authentication is the process of verifying the identity of a user or system, which is a critical first step in ensuring that the individual is who they claim to be. This is crucial because inadequate authentication measures can lead to unauthorized access, which compromises security. Adding a second factor, or two-factor authentication (2FA), enhances security by requiring two pieces of evidence (or factors) before granting access: something the user knows (like a password), and something the user has (like a mobile device).