What best describes the function of the IP routing table in a router?

The function of the IP routing table in a router is best described by the option that states it determines which device to send packets to next. This table contains network routes, which include the destination IP addresses and the associated next hop IP addresses or exit interfaces that the router should use to forward packets toward their destination. When a packet arrives at the router, the router analyzes the destination IP address and uses the routing table to decide the most appropriate path for the packet to take. This process ensures efficient and accurate delivery of data across networks and is fundamental to the operation of network routing.

In contrast, forwarding frames based on layer-2 addresses pertains to the functionality of a switch and its MAC address table, rather than a router's IP routing table. Handling MAC addresses is also a task associated with layer-2 devices, while caching ARP entries is related to mapping IP addresses to MAC addresses for local devices; this is a different function primarily managed by the Address Resolution Protocol (ARP) and does not involve decision-making based on routing tables.