Is it option D?
Ans is C, referential integrity constraints are specified between two relations in a schema
Whenever two tables contain one or more common columns, RDBMS can enforce the relationship between the two tables through a referential integrity constraint. Define a PRIMARY or UNIQUE key constraint on the column in the parent table (the one that has the complete set of column values). Define a FOREIGN KEY constraint on the column in the child table (the one whose values must refer to existing values in the other table).
For more references, please refer to the link https://docs.oracle.com/cd/B10500_01/appdev.920/a96590/adg05itg.htm