Which statement is true about Data Guard implementation in Oracle Cloud Infrastructure (OCI) bare metal and virtual machine database systems? 

Answer options:

A. Both database systems must be in the same compartment.
B. Primary and standby database versions and editions need not be identical.
C. Primary and standby databases must be in the same OCI region.
D. Database systems need not be the same shape type (e.g., primary database can be a virtual machine, and standby database a bare metal shape, and vice versa).

A

Reference: https://docs.cloud.oracle.com/en-us/iaas/Content/Database/Tasks/exausingdataguard.htm