Green eggs and ham cat in the hat were his most successful.
There are several options for this, but one main word to describe this would be "inefficiently", which is an adverb in this sense that says the person was no efficient.
I would go with Readers' Guide, because it lists hundreds of magazines. 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 <3