Which statement about communication over failover interfaces is true?

A.
All information that is sent over the failover and stateful failover interfaces is sent as clear text by default.

B.
All information that is sent over the failover interface is sent as clear text, but the stateful failover link is
encrypted by default.

C.
All information that is sent over the failover and stateful failover interfaces is encrypted by default.

D.
User names, passwords, and preshared keys are encrypted by default when they are sent over the failover
and stateful failover interfaces, but other information is sent as clear text.

Explanation:
BD
All information sent over the failover and Stateful Failover links is sent in clear text unless you secure the
communication with a failover key. If the security appliance is used to terminate VPN tunnels, this information
includes any usernames, passwords and preshared keys used for establishing the tunnels. Transmitting this
sensitive data in clear text could pose a significant security risk. We recommend securing the failover
communication with a failover key if you are using the security appliance to terminate VPN tunnels.
Source: http://www.cisco.com/c/en/us/td/docs/security/asa/asa80/configuration/guide/conf_gd/failover.html