Which three statements about OSPFv2 or OSPFv3 authentication are true? (Choose three.)

A.
On Cisco IOS XR platforms, OSPFv3 authentication can be configured at the OSPF routing
process, area, or interface level.

B.
OSPF authentication on Cisco IOS and IOS XE platforms can be configured per area or per
interface.

C.
On Cisco IOS and IOS XE and IOS XR platforms, the authentication key can only be configured
per interface.

D.
OSPFv3 uses IPsec for authentication and encryption.

E.
On Cisco IOS XR platforms, the OSPF authentication that is configured for the area overrides
the authentication that is configured for the interface.

F.
On Cisco IOS and IOS XE platforms, the two OSPFv2 authentication methods that are
supported are MD5 and SHA1.

Explanation:
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.7/routing/configuration/guide/rc37ospf.html