(A) To ensure you can always access the original data
(B) In order to configure Goals
(C) In order to use a filter for multiple views
(D) There is no reason to have an unfiltered view
It is important to keep one unfiltered view because you need to have a backup copy of your original View data which you can access anytime. You can also use this unfiltered original View to review the changes you make after creating a new View.
This question is a part of the Assessment section of the Google Analytics For Beginners Certification course. You can find the answers with full explanation for all the assessment questions on our Google Analytics For Beginners Assessment 1 Answers page, and Google Analytics for Beginners Assessment Answers page.