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.
Answer: A,B,D