Select type

List
Select to create a non-hierarchical (also called "list" ) marking set containing one or more markings, each independent of all others. This type of marking set can be assigned to either single or multi-valued properties.
Hierarchical
Select to create a hierarchical marking set that arranges markings in a simple, single branch series. Each hierarchical marking has a superior marking in the same set, except for the first, or top marking. Hierarchical marking sets support an order of precedence when evaluating access rights. A marking in a hierarchical marking set explicitly grants access rights to some set of security principals. In addition, it also implicitly grants the same rights for all markings that are inferior to (or below) it in the hierarchy. Hierarchical marking sets can be assigned only to single-valued properties.