For an Attribute to Be Loaded on a Catalog/product Object

For an attribute to be loaded on a catalog/product object, which two of the following conditions must be satisfied?

A) The eav_attribute table must contain a row defining the attribute's properties and its entity type.
B) The attribute must have a backend model configured in the XML config.
C) The attribute must be part of the attribute set pertaining to the object being loaded.
D) There must be a record of the attribute on the catalog_product_super_atti:ibute table,
E) There must be a column added to the catalog_product_entity table.