Which layer in the OSI model is concerned with addressing and routing?

The correct choice focuses on the Network layer, which is the third layer of the OSI model. This layer is pivotal in handling the operations that relate to the routing and forwarding of data packets across multiple networks. It is responsible for logical addressing, which means that it assigns IP addresses to devices on the network. This addressing is essential for determining the best path for data to travel from the source to the destination, especially in complex networks where multiple paths exist.

The Network layer implements routing protocols, such as RIP, OSPF, and BGP, which help in making decisions about how data should be routed through various intermediary devices like routers. These protocols ensure that data is efficiently directed to its final destination, taking into account factors like network topology and congestion. Understanding how the Network layer functions is crucial for grasping how data traverses through diverse geographic locations and networks.

The other layers mentioned do not focus on routing and addressing. The Transport layer deals with end-to-end communication and data flow control, the Session layer manages sessions between applications, and the Application layer provides interface protocols for user applications. None of these layers are directly responsible for the routing and addressing functions that are unique to the Network layer.