Can a category in an outline have only one entry?
The answer is no. By convention, each category consists of a minimum of two entries. If your first category is Roman numeral I, your outline must also have a category labeled roman numeral II; if you have a capital letter A under category I, you must also have a capital letter B. Whether you then go on to have capital letters C, D, E, etc., is up to you, depending on the amount of material you are going to cover.
