Refer to the exhibit. A network engineer must enable multicast on the network to support a new business initiative launching multicast-based company TV. The multicast source connects to Layer 3 switch SW_1 with IP address `172.16.12.1`. `ip multicast-routing` has been configured on SW_1, and CoPP policies across the LAN segment have been adjusted to permit IP protocol number 103. All hosts in the network must receive the TV flow, but they must be allowed to prune themselves from it. Which task must the engineer perform to meet the objective?