The correct answer is (B) Process-to-process delivery.

Explanation:

• The transport layer in the ISO-OSI model is responsible for process-to-process delivery of data. This means that it ensures data is correctly transferred between the application processes running on different systems.
• The transport layer is also responsible for error correction, flow control, and maintaining end-to-end communication. Examples of transport layer protocols include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).