Which of the following steps in the troubleshooting methodology is used to strategically eliminate known...

Testing the theory to determine the cause is the troubleshooting step used to strategically eliminate possible causes before confirming the main source of the issue. After the problem is identified and a theory of probable cause is established, the technician must test that theory. If the test confirms the theory, the technician can move toward creating a plan of action. If the theory is not confirmed, the technician should establish a new theory or escalate the issue.

The CompTIA Network+ N10-009 troubleshooting methodology emphasizes a structured process to avoid guessing and unnecessary changes. Testing a theory may include checking configurations, replacing a suspected cable, reviewing logs, verifying connectivity, testing DNS resolution, checking VLAN assignments, or comparing results against known-good systems. This process helps narrow the issue by ruling out causes that do not match the evidence.

Identifying the problem is the first step and involves gathering information. Establishing a theory means forming a likely explanation. Establishing a plan of action happens after the cause is confirmed. Therefore, the step that best matches strategically eliminating known issues is testing the theory to determine the cause.