Refer to the exhibit. When router R1 is sending traffic to IP address 10.56.192.1, which interface or next hop address does it use to route the packet?

Routers determine the outbound interface or next-hop IP address for a destination by performing a longest prefix match against their routing table. For destination 10.56.192.1, the routing table on R1 must contain an entry that specifies 10.56.0.1 as the next hop for the subnet containing 10.56.192.1.

The 0.0.0.0/0 default route is used only when no more specific route exists in the routing table for the destination IP address.

Vlan57 is an interface, but routing decisions typically involve a next-hop IP address for remote networks, or direct connection if the destination is on the same subnet.

10.56.128.19 would be a next-hop only if a more specific route for 10.56.192.1 pointed to it, or if it was part of an equally specific route but less preferred.