Implementing 'user access rights based on job roles' ensures that every user has just enough access to perform their designated tasks, without additional permissions that could expose the system to unnecessary risks. This aligns with the least privilege principle, which aims to reduce the risk of unauthorized access to sensitive data and systems by minimizing user rights. By assigning permissions strictly based on job roles, the risk surface is reduced, and security is enhanced. 'Open access to all users' contradicts the principle, as it gives more privileges than necessary, potentially leading to data breaches. 'Admin rights for department heads' gives unnecessary high-level access, which also violates the least privilege principle. 'Network access based on seniority' does not consider the actual job requirements and can lead to both overprivileged and underprivileged users, which is not aligned with security best practices.