What type of article expresses the opinion of an editor or publisher in a newspaper or magazine?

The type of article that expresses the opinion of an editor or publisher in a newspaper or magazine is an editorial. Editorials are typically written to provide commentary on current events or issues, offering the publication's stance or perspective. They aim to influence public opinion or provoke thought and discussion among readers. In contrast, expository writing focuses on delivering information and explanations without imparting personal opinions; problem/solution writing presents a specific issue and explores potential solutions; and functional/technical writing is designed to convey instructions or technical information clearly and effectively. Thus, the editorial stands out as the correct choice since it specifically embodies the subjective viewpoint of the publication's editorial staff.