Which command will ensure that R2 will be the primary router for traffic using the gateway address of 172.16.15.20?

Which command will ensure that R2 will be the primary router for traffic using the gateway address of 172.16.15.20?
Exhibit

A.
On R2 add the command standby 1 priority 80

B.
On R1 add the command standby 1 priority 110

C.
On R1 add the command standby 1 priority 80

D.
On R2 remove the command standby 1 preempt

Explanation:

HSRP election is based on a priority value (0 to 255) that is configured on each router in the group. By default, the priority is 100. The router with the highest priority value (255 is highest) becomes the active router for the group. If all router priorities are equal or set to the default value, the router with the highest IP address on the HSRP interface becomes the active router. To set the priority, use the following interface configuration command:
Switch(config-if)# standby group priority priority

When HSRP is configured on an interface, the router progresses through a series of states before becoming active. This forces a router to listen for others in a group and see where it fits into the pecking order. The HSRP state sequence is Disabled, Init, Listen, Speak, Standby, and, finally, Active.