For a Unary M:N Relationship

Multiple Choice

For a unary M:N relationship:

A) the entity type is modeled as one relation; a separate relation is created to represent the M:N relationship; the new relation has a composite key that consists of two attributes that both take their values from the same primary key.
B) the entity type and the M:N relationship are modeled as one relation; a composite key consisting of two attributes that both take their values from the same primary key is used as the primary key for the relation.
C) separate relations for the class and for each subclass are created; primary and foreign keys are established for each class.
D) the primary key of the entity on the one side of the relationship serves as a foreign key in the relation on the many side of the relationship.
E) none of the above is true.