To answer this question, we need to understand the concept of system accounts and their usage.
System accounts are user accounts that are used by the operating system or specific applications to perform various system-level tasks. These accounts typically have elevated privileges and are used for administrative purposes.
Ordinary users (option A) should not be allowed to use system accounts because they do not require the elevated privileges that system accounts provide. Allowing ordinary users to use system accounts can pose a security risk as they may unintentionally or maliciously misuse the elevated privileges.
Security administrators (option B) are responsible for managing and enforcing security policies within an organization. While security administrators may have a higher level of access compared to ordinary users, they should also not have direct access to system accounts. Instead, they should have their own separate administrative accounts that are specifically designed for managing security-related tasks.
System administrators (option C) are responsible for managing and maintaining the overall operation of computer systems and networks. While system administrators may have the knowledge and expertise to handle system accounts, it is generally recommended that they use their own administrative accounts for system-level tasks instead of directly using system accounts.
Therefore, the correct answer is option D - None of the above. No type of users should be allowed to use system accounts, as these accounts should be reserved solely for system-level tasks and administration.