Final answer:
The easiest method to disable an account when an employee leaves is to use Single Sign-On (SSO), as it centralizes authentication services across multiple systems.
Step-by-step explanation:
The most straightforward method to disable an account when an employee leaves a company is to use Single Sign-On (SSO). SSO centralizes session and user authentication services, which means you only need to turn off one set of login credentials to deny access across multiple systems and applications. While enforcing multi-factor authentication (MFA) enhances security and monitoring sign-on attempts can indicate suspicious behavior, these methods are not primarily designed to simplify the process of disabling an account. Single Sign-On simplifies user management and ensures a quick response when access needs to be revoked.