When making changes to a server， which of the following is the BEST way to troubleshoot a problem？（）

• A、 Perform root cause analysis and then test the theory to determine the cause.
• B、 Make changes to the system and document everything once the problem is resolved.
• C、 Make multiple changes to all affected areas to resolve all potential issues.
• D、 Make a change and if the problem is not resolved， reverse the change.