A. Schema owners indeed can grant privileges on objects in their schema to other users or roles, making this statement true.
B. Roles in Oracle can be granted both object and system privileges, making this statement true as well.
C. Not all types of schema objects have associated object privileges. For example, synonyms do not have object privileges because they are just aliases for other objects.
D. The DBA role is a powerful role, but creating roles can be done by any user granted the necessary privileges, not just users with the DBA role.
E. Object privileges on a table do not automatically apply to all synonyms for that table. Synonyms are separate objects that must have privileges granted explicitly.
F. The privilege to grant system privileges is controlled by the GRANT ANY PRIVILEGE system privilege, making this statement true.
References:
Oracle Database SQL Language Reference, 12c Release 1 (12.1): "Privileges"
Oracle Database Security Guide, 12c Release 1 (12.1): "Administering User Privileges, Roles, and Profiles"