Solution

The correct answer is A - III, B - I, C - II, D - IV

Key Points

• A. Physical layer -
  • ​It is the lowest layer of the OSI model and it deals with the transmission and reception of the unstructured raw bit stream over a physical medium. So, it corresponds to III. Transmission of raw bits over communication channel.
• B. Data Link Layer -
  • ​It is responsible for the node-to-node delivery of the packet. It transforms raw bits into frames, so it corresponds to I. Transforming the raw bits in the form of frame for transmission.
• C. Network layer -
  • It decides which physical path the data will take based on the network conditions, the priority of service, and other factors. Thus, it corresponds to II. Control and monitoring of subnet.
• D. Transport layer -
  • It provides transparent transfer of data between devices and can use either connection oriented communication or connectionless, so it corresponds to IV. Datagrams transmission data through connection oriented or connectionless using datagram.