正解:A
In normal Hot Standby Router Protocol operation, the active HSRP interface answers ARP requests, but with a vPC, both HSRP interfaces (active and standby) can forward traffic.
The most significant difference between the HSRP implementation of a non-vPC configuration and a vPC configuration is that the HSRP MAC addresses of a vPC configuration are programmed with the G (gateway) flag on both systems, compared with a non-vPC configuration, in which only the active HSRP interface can program the MAC address with the G flag. Given this fact, routable traffic can be forwarded by both the vPC primary device (with HSRP) and the vPC secondary device (with HSRP), with no need to send this traffic to the HSRP primary device.
Without this flag, traffic sent to the MAC address would not be routed.