What is not a part of the format for a letter to the editor?

Double spacing-+? This question is confusing because I'm not sure what it's supposed to be compared to, is it a multiple choice question? What IS apart of the format to a letter to an editor is your name and address preferably on the top right and the editor's name and address in the top left of the header, a proper intro, a salutations, correct indentation and paragraph spacing, and to make your point and end your train of thought properly to capture your reader's attention.