A. Do not enter a value in the primary key field of chield table if that value does not exist inthe primary key of the parent table
B. Do not enter a value in the foreign key field of a parent table if that value doesnot exist in the primary key of the child table
C. Do not enter a value in the foreign key field of a child table if that value does not exist in the primary key of the parent table
D. Do not enter a value in the foreign key field of child table if that value does not exist inthe foreign key of the parent table