*Option (H). It says precisely what it means in a Wikipedia-like fashion. (A) may be the most common name, but we have the additional task of disambiguating it from the legal instrument.  (C) is too colloquial, and literally false.  (F) is bad because most legal experts do not consider that a mandate is a type of protectorate (Wright, Mandates under the League of Nations, p317). (G) is the one that sounds nicest but maybe it's too cute for a title(?).