Which of the following does Joe need to implement in order to enforce accountability?

Joe needs to track employees who log into a confidential database and edit files. In the past, critical files
have been edited, and no one admits to making the edits. Which of the following does Joe need to
implement in order to enforce accountability?

A.
Non-repudiation

B.
Fault tolerance

C.
Hashing

D.
Redundancy