The process of making certain that an entity (operating system, application, etc.) is as secure as it can be
known as:

A.
Stabilizing
B.
Reinforcing
C.
Hardening
D.
Toughening
Explanation:
Hardening is the process of securing a system by reducing its surface of vulnerability. Reducing the surface of
vulnerability typically includes removing unnecessary functions and features, removing unnecessary usernames
or logins and disabling unnecessary services.