Which command configures an HSRP group to become a slave of another HSRP group?

A.
standby slave

B.
standby group track

C.
standby follow

D.
standby group backup

Explanation:
Perform this task to configure multiple HSRP client groups. The “standby follow” command configures an HSRP group to become a slave of another HSRP group.
HSRP client groups follow the master HSRP with a slight, random delay so that all client groups do not change at the same time.
http://www.cisco.com/en/US/docs/ios-xml/ios/ipapp_fhrp/configuration/15-mt/fhp-hsrp- mgo.html