QUESTION $8$ What is a "meaningful" identifier? Select the best answer from the following. A$.$ This generally is a key that contains sensitive information that needs to be protected. B$.$ This generally is a key where the value of the key carries implicit meaning. C$.$ This is a key that will never be changed because the information it contains must never be lost. D$.$ A "meaningful" identifier is always the same as a foreign key in a relationship.