What are the default values for GRE tunnel keepalive time and number of retries?

A.
5 seconds and 3 retries

B.
10 seconds and 5 retries

C.
10 seconds and 3 retries

D.
20 seconds and 5 retries

E.
5 seconds and 5 retries

Explanation:
This output shows the commands you use in order to configure keepalives on GRE tunnels.
Router# configure terminal
Router(config)#interface tunnel0
Router(config-if)#keepalive 5 4
!— The syntax of this command is keepalive [seconds [retries]].
!— Keepalives are sent every 5 seconds and 4 retries.
!— Keepalives must be missed before the tunnel is shut down.
!— The default values are 10 seconds for the interval and 3 retries.