Answer: B. system accounts, contingent IDs
Step-by-step explanation:
Aside from human user types, there are non human user groups. Known as account types, (system accounts) are implemented by the system to support automated services, and contingent IDs are accounts that remain non human until individuals are assigned access and can use them to recover a system following a major outage. The system account is refered to as the user account which the operating system creates during installation.
Therefore, the correct option is B.