Which of the following is NOT a common type of computer software?

The identification of network protocol software as not being a common type of computer software is accurate because it does not fit into the three established categories of computer software: system software, application software, and utility software.

System software refers to the operating systems and all underlying software that support the computer's basic functions and manage hardware resources. Application software encompasses programs designed for end-users, enabling tasks like word processing, web browsing, and database management. Utility software provides essential functions for maintaining and optimizing the performance of a computer, such as antivirus software and disk management tools.

Network protocol software, while important for communication between devices over a network, does not belong to the same structural categories as the others. It represents specific sets of rules and standards (like TCP/IP) that govern how data is transmitted over a network rather than a standalone software category that provides general functions for a computer system. Thus, it stands apart from the commonly recognized software types.