What do you call that reference that has the lists available magazine articles alphabetically by subject? a. newspaper index b. card catalog c. readers' guide

The correct answer is C. Reader's guide. 

Usually, there is a reference list for all the available magazine articles that is arranged alphabetically by subject. This is called a reader's guide. A newspaper index is a reference for newspapers base on the issue date while a card catalog is a reference in finding authors of books. So the correct answer is C. I hope this answer helped you. 

Iwould have to say a

Pretty sure it’s computers