Which of the Following Is a Rule of Referential Integrity

Multiple Choice

Which of the following is a rule of referential integrity? ​

A) A record can be added to a related table even if a matching record exists in the primary table.
B) The value of the primary key in the primary table cannot be changed if matching records exist in a related table.
C) A record in the primary table can be deleted if matching records exist in the related table.
D) The Cascade Delete Related Records option cannot be used to delete records in the primary table as well as in a related table.