Which of the following defines a protocol?

systems used to control access to a network
nodes used to ensure that messages are sent and received at their proper places
rules that check the reliability of data within a network
rules for organizing data sent through a communications network

Protocol can be defined as a set of rules for organizing data sent through a communications network

Explanation:

A protocol can be defined as a rules that helps in connecting and exchanging messages or data between any devices in a network.  It ensures whether the data is sent and received properly by the two devices in the network. It plays a major role in the communication process in a network.

Protocols are generally a set of rules that are used for the organisation of data in a network. It clearly shows how a data can be packed and sent through a network. For sending and receiving the messages they use packet switching techniques. They make the data into smaller pieces(packets) at the sender end and integrates into the original message at the receiving end.

Amendment XVIII i believe this is the correct answer