正解:B
In a vPC (Virtual Port Channel) configuration, multicast traffic is handled based on the IGMP (Internet Group Management Protocol) and PIM (Protocol Independent Multicast) configurations. When a host sends traffic to a multicast group, the vPC switches determine the forwarding path based on the multicast routing table and the RPF (Reverse Path Forwarding) check.
Option B is correct because when multicast traffic with source address 10.10.10.10 targeting group 239.1.1.1 is received on Po10 Switch1, the switch will perform an RPF check and forward the traffic out of the interfaces that lead to the Rendezvous Point (RP) and the receivers. This ensures that the multicast traffic is efficiently distributed to all receivers that are part of the multicast group. The traffic would be forwarded out on Po1, which is typically connected to the RP, and Po20, which connects to other receivers in the network.
References := For more detailed information on multicast traffic forwarding in a vPC environment, please refer to Cisco's official documentation on Implementing Cisco Data Center Core Technologies (DCCOR), specifically the sections discussing multicast routing and vPC configurations.