A.backup interface 1 10; backup interface 2 20
B.backup interface serial 1 10; backup interface serial 2 20
C.backup interface 1 priority 10; backup interface 2 priority 20
D.backup interface serial 1 priority 10; backup interface serial 2 priority 20
A.dialer-list
B.access-list
C.dialer-group
D.dialer in-band