Which of the following is an example of an imperative sentence?

According to the mla format, which best demonstrates the similarities and differences between the citations of a magazine and a book? both require the title and author, while magazines require the editor of the magazine. both require a date of publication, while magazines require the page number of the article. both require the format of the book, while books require the page number of the information. both require a location of publication, while books require the edition of the book if there is more than one.