Which term describes measures to protect a computer system from unauthorized access?

The term that describes measures to protect a computer system from unauthorized access is "Cybersecurity." This field encompasses a wide range of practices, technologies, and policies designed to safeguard computers, networks, and data from damage, theft, or unauthorized access. Cybersecurity involves implementing security measures, such as firewalls, encryption, and intrusion detection systems, to protect sensitive information and maintain the integrity of systems.

In the context of computer systems, effective cybersecurity strategies help ensure that only authorized users can access data and resources, thus mitigating risks from cyber threats like hacking, phishing, and malware. This is crucial in an increasingly digital world where breaches can have serious ramifications for individuals and organizations alike.

The other terms refer to different concepts: "Computer Network" pertains to a group of interconnected computers; "Productivity Software" refers to software designed to help users complete tasks efficiently, such as word processing or spreadsheets; and "Presentation Software" specifically relates to tools for creating visual presentations, such as slideshows. None of these focus on security measures, which is why "Cybersecurity" is the correct term in this context.