Which two are true about common objects? (Choose two.) 

Answer options:

A. They can be created only in CDB$ROOT.
B. They can be only metadata-linked in an application container.
C. They can exist in user-defined schemas only in application containers.
D. They can exist in CDB$ROOT and an application root.
E. They can be extended data-linked in CDB$ROOT.
F. They can be created only in an application root.

EF

Reference: https://blog.toadworld.com/2017/08/01/oracle-multi-tenant-application-containers-part-iii-sharing-of-data-in-application-common-objects