Which of the following best describes the ON DELETE NO ACTION referential integrity constraint?

A.
If a parent key is deleted, any child keys referenced by the parent key are automatically deleted.

B.
If a parent key is deleted, no test is made for referential integrity.

C.
If any child key references a parent key, the record containing the parent key cannot be deleted.

D.
If a parent key is deleted, all child keys are automatically set to a specified value.