When multiple menu options are displayed in a list, each option should be displayed on a new line, i.e., format the list as a single column.
Additional Information:
Displaying options in several columns may be used where shortage of display space dictates a compact format. If there are only a few options, those might be displayed in a single row. An exception could be made for hierarchic menus, where a high-level menu might be shown in the left column of a display, accompanied by a lower-level menu in the right column whose options change to reflect whatever selection is currently made from the high-level menu. A single column format will aid scanning, especially for novice users.