Explanation: A system usage agreement is a document that defines the rules and expectations for using a company’s IT resources, such as computers, networks, intranets, software, and data. A system usage agreement typically covers topics such as acceptable use, security, privacy, monitoring, ownership, and consequences of violations. A system usage agreement helps to protect the company’s assets, reputation, and legal compliance, as well as the users’ rights and responsibilities. Privacy expectations on a company intranet should be limited to what is stated in the system usage agreement, as the company has the right and the duty to monitor and control the intranet for business purposes. Users should not assume that their activities on the intranet are private or confidential, unless the system usage agreement explicitly guarantees such privacy. The other options, such as precedents, HR policy, and word of mouth, are not reliable or consistent sources of privacy expectations, as they may vary, change, or conflict with the system usage agreement or the law. References: CompTIA IT Fundamentals (ITF+) Certification Guide, page 100; 10 Intranet Best Practices for a Successful Intranet in 2021, point 7.