Which of the following FSMO roles exist?

Flexible Single Master Operations (FSMO) roles, also known as operations master roles, are specialized domain controller tasks in an Active Directory environment. The FSMO roles include:

C. PDC Emulator

The Primary Domain Controller (PDC) Emulator is responsible for synchronizing time and managing password changes.

D. RID Master

The Relative ID (RID) Master allocates blocks of RIDs to each domain controller in the domain.

References:

Microsoft Docs - FSMO Roles