Answer:
Document property is the correct answer.
Explanation:
Because when you take a property of your documents than you can set the attribute of your document as a read only option. simply check the box of Read-only and click apply and click OK button.
in this way your file will be read only, when you open it and edit it and save it than save as option will be open that first save as new name this file and than you edited work will be saved.
