An administrator has been working within an organization for over 10 years. he has moved between different it divisions within the company and has retained privileges from each of the jobs that he's had during his tenure. recently, supervisors admonished him for making unauthorized changes to systems. he once again made an unauthorized change that resulted in an unexpected outage and management decided to terminate his employment at the company. he came back to work the following day to clean out his desk and belongings, and during this time he installed a malicious script that was scheduled to run as a logic bomb on the first day of the following month. the script will change administrator passwords, delete files, and shut down over 100 servers in the datacenter.
what could have discovered problems with this user's account while he was employed?
a. policy requiring strong authentication
b. multifactor authentication
c. logging
d. account review