Which layer of a computer network handles routing of data packets?

The correct answer is the network layer, which is responsible for routing data packets from the source to the destination across multiple networks. This layer determines the best path for data transmission and makes decisions based on factors like network congestion and distance. It utilizes logical addressing, such as IP addresses, to identify devices on a network, and it handles the forwarding of packets through different routers.

In this context, the application layer is focused on user interface and application-level functions, while the transport layer is responsible for end-to-end communication and reliability, managing flow control and error checking. The data link layer, on the other hand, is responsible for the transfer of data frames between adjacent network nodes and does not involve routing beyond a single network segment. Thus, the network layer is the pivotal component in ensuring data reaches its intended destination across varying network paths.