Which two statements are true?

Which two statements are true?

A.
A role cannot be assigned external authentication.

B.
A role can be granted to other roles.

C.
A role can contain both system and object privileges.

D.
The predefined resource role includes the unlimited_tablespace privilege.

E.
All roles are owned by the sys user.

F.
The predefined connect role is always automatically granted to all new users at the time of their
creation.

Explanation:
http://docs.oracle.com/cd/E11882_01/network.112/e36292/authorization.htm#DBSEG99878 (the
functionality of roles)