Which order do the following events need to occur before the catalog server is ready?

A global catalog server is available to directory clients when Domain Name System (DNS) servers can locate it as a global catalog server. In which order do the following events need to occur before the catalog server is ready?
A) The Net Logon service on the domain controller has updated DNS with global-catalogspecific service (SRV) resource records.
B) The isGlobalCatalogReadyrootDSE attribute is set to TRUE.
C) The global catalog receives replication of read-only replicas to the required occupancy level.
A. C then A, then B
B. B then C, then A
C. A then C, then B
D. C then B, then A