Answer:
A. service account
Step-by-step explanation:
Service account is a special user account that an application or service uses to interact with the operating system. Services use the service accounts to log on and make changes to the operating system or the configuration.
Shared account is used for situations where multiple users share the same computer
System account is used by the operating system
Privileged accounts are named credentials that have been granted administrative privileges on one or more systems.