If you apply a filter to a view, only the data from the time when the filter was applied will be affected. You cannot go back and apply a filter to your historical data.
Only, the data after the filter was created will change and the historical data before the application of the filter will remain intact.
This question is a part of the Assessment 2 section of the Advanced Google Analytics Certification course. You can find the answers with full explanation for the second Assessment in our Advanced Google Analytics Assessment 2 Answers page or you can check out the answers for all the assessment questions in our Advanced Google Analytics Assessment Answers page.