The correct answer is: D. network layer
The network layer is responsible for routing data packets through a network. It does this by maintaining a routing table, which is a list of all the known networks and the best way to reach them. When a data packet is sent, the network layer looks up the destination address in the routing table and forwards the packet to the next hop on the path to the destination.
The session layer is responsible for managing communication sessions between two applications. It does this by establishing, maintaining, and terminating sessions.
The transport layer is responsible for providing reliable data transfer between two applications. It does this by breaking up data into smaller packets, adding error detection and correction codes, and sequencing the packets.
The data link layer is responsible for transferring data between two nodes on a network. It does this by framing data into packets, adding error detection and correction codes, and controlling access to the network.
None of the above options are correct.