Which of the following elements of a newspaper displays the name of the paper? a. sidebar b. banner c. subhead d. headline

The correct option would be  D Headline. It might be defined as "a statement printed in large letters at the beginning of a newspaper article, summarizing the subject of the article" 
As regards the rest of the terms, their definitions are: 
Sidebar: "a short story related to the main story and run adjacent to it"
Banner: "a headline that runs across all eight columns on the top of the page. It is used for momentous events".
Subhead:  "one or two words headline inserted at the head of a paragraph to break the monotony of a solid column of type".