Which layer of the OSI model is responsible for data formatting and encryption?

The correct response is the Presentation layer. This layer is crucial in the OSI model as it acts as a translator between the application layer and the network. Its primary responsibilities include data formatting, which ensures that data is presented in a readable format for different types of systems and applications. This encompasses tasks such as converting character sets, graphics, or data compression.

Additionally, the Presentation layer handles encryption and decryption processes, which are essential for securing data during transmission. By managing these tasks, it allows the layer above it—the Application layer—to focus solely on providing network services and user-facing functionalities without needing to worry about how data is formatted or secured.

The other layers mentioned do not perform these functions. The Transport layer primarily deals with end-to-end communication, ensuring reliable data transfer between hosts. The Session layer manages sessions and controls the dialogue between two systems, establishing, maintaining, and terminating connections. The Application layer provides services directly to user applications but does not concern itself with the specifics of how that data is presented or encrypted. Each layer has its specialized functions, but the Presentation layer is specifically designed for the tasks of data formatting and encryption.