____ hours are work hours outside of those specified by the calendar.

A user can add ________ to the criteria for a field in the design grid to return results where there is nothing in that field

A) Is Empty B) Is Null C) Is Not Null D) Is Not Empty

More complex DBMSs maintain a(n) ______, which is a listing of activities that modify the contents of the database.

Fill in the blank(s) with the appropriate word(s).