Rows in a table can sometimes be grouped into subcategories of the primary entity type. It becomes appealing to create Subtypes of the main Supertype table if certain conditions are true. Mark all of the valid reasons you would want to separate a table into a Supertype / Subtype relationship. When a subcategory of rows has a relationship with another table not shared by the rest of the rows. When a subcategory of rows has NULLability not shared by the rest of the rows. When a subcategory of rows has 1 or more unique columns not shared by the rest of the rows