Which command will ensure that External_B will be the primary router for traffic using the gateway address of
172.16.15.20?
A.
On External_B add the command standby 1 priority 80
B.
On External_A add the command standby 1 priority 110
C.
On External_A add the command standby 1 priority 80
D.
On External_B remove the command standby 1 preempt