What are three benefits of GLBP? (Choose three.)

A.
GLBP supports up to eight virtual forwarders per GLBP group.

B.
GLBP supports clear text and MD5 password authentication between GLBP group members.

C.
GLBP is an open source standardized protocol that can be used with multiple vendors.

D.
GLBP supports up to 1024 virtual routers.

E.
GLBP can load share traffic across a maximum of four routers.

F.
GLBP elects two AVGs and two standby AVGs for redundancy.

Explanation:
http://www.cisco.com/en/US/docs/ios/12_2s/feature/guide/fs_glbp2.html
Load Sharing You can configure GLBP in such a way that traffic from LAN clients can be shared by
multiple routers, thereby sharing the traffic load more equitably among available routers. Multiple
Virtual Routers GLBP supports up to 1024 virtual routers (GLBP groups) on each physical interface of
a router, and up to four virtual forwarders per group.
Preemption The redundancy scheme of GLBP enables you to preempt an active virtual gateway with
a higher priority backup virtual gateway that has become available. Forwarder preemption works in
a similar way, except that forwarder preemption uses weighting instead of priority and is enabled by
default.
Authentication You can use a simple text password authentication scheme between GLBP group
members to detect configuration errors. A router within a GLBP group with a different
authentication string than other routers will be ignored by other group members.
http://www.cisco.com/en/US/docs/switches/datacenter/sw/5_x/nxs/unicast/configuration/guide/l3_glbp.html
GLBP Authentication GLBP has three authentication types: MD5 authentication Plain text
authentication No authentication MD5 authentication provides greater security than plain text
authentication. MD5 authentication allows each GLBP group member to use a secret key to generate
a keyed MD5 hash that is part of the outgoing packet. At the receiving end, a keyed hash of an
incoming packet is generated. If the hash within the incoming packet does not match the generated
hash, the packet is ignored. The key for the MD5 hash can either be given directly in the
configuration using a key string or supplied indirectly through a key chain. You can also choose to
use a simple password in plain text to authenticate GLBP packets, or choose no authentication for
GLBP.