Which statement about NOT ENFORCED unique constraints is TRUE?
A . NOT ENFORCED unique constraints can not be defined on primary key columns
B . The query optimizer will consider a NOT ENFORCED unique constraint when selecting an optimal data access plan
C . When attempting to insert data that does not conform to a NOT ENFORCED unique constraint, awarning will be returned
D . Storage requirements for a NOT ENFORCED unique constraint are no different than the storage requirements for a similar unique index
Answer: B