A server administrator notices an unauthorized user has made changes to a database server. In which of the following troubleshooting methodologies is the server administrator currently involved?

Testing a theory to determine cause comes after a probable cause has already been identified and hypothesized, which has not yet occurred in this scenario.

Establishing a theory of probable cause comes after the scope has been determined; the administrator has not yet begun hypothesizing why or how the unauthorized access occurred.

Verifying full system functionality is the final troubleshooting step, performed only after a remediation has been applied, which has not happened in this scenario.

Determining the scope of the issue is the troubleshooting step where the administrator identifies what systems or data were affected and the extent of the problem. Recognizing that an unauthorized user has made changes to a database server is precisely this step - the administrator is assessing what occurred and how broadly it impacted the environment before forming theories or testing solutions.