Final answer:
In ServiceNow, User Criteria are primarily used to control read and write access to Knowledge bases and articles, ensuring that only authorized users can access sensitive information or applications.
Step-by-step explanation:
In the base ServiceNow instance, User Criteria are used for a variety of purposes related to controlling access and visibility of content within the platform. Specifically, User Criteria can indeed control read and write access to Knowledge bases and articles, which is option 3. This means that administrators can set specific conditions that must be met by users in order to view or edit Knowledge base content. It ensures that sensitive information is only available to authorized users. Additionally, User Criteria are also used to personalize the user experience by controlling access to applications, portals, and widgets such as information and suggested reading widgets on dashboards. Therefore, while User Criteria can play a role in determining who can see what on HR Service Portals and the HR Case application, they are most directly associated with Knowledge management.