a) How does a company addn.,ss the problem of changing login credentials and permissions on various servers for an employee when he or she moves to a different department? b) What does a company do...

a) How does a company addn.,ss the problem of changing login credentials and permissions on various servers for an employee when he or she moves to a different department? b) What does a company do when an employee is terminated to ensure that no authentication server will give that person access to any resource? c) What is role-based access control? d) What are its advantages compared to assigning permissions based on individuals?