When a manager asks when testing will be complete, the most appropriate and informative resource to provide an answer is test progress reports (Option A). Test progress reports contain detailed information on the status of testing activities, including what has been accomplished, what remains to be done, the results of the tests conducted, and any issues or risks that might impact the completion of testing. These reports allow for an informed assessment of the testing progress and estimation of when testing might be completed. Options B, C, and D do not provide the structured, detailed, and specific information required to accurately answer the manager's question about the completion of testing.