In microsoft Access:

$11.$ Open the GuestAndWorkshop query in Design View and make the following changes to the query:

a$.$ Add the RegistrationFee field to the query design grid immediately following the AttendeeID field.

b$.$ Add criteria to select only those records where the GuestFee field value equal $0$ and the WorkshopFee equal $0.$

Open the query in Datasheet View and confirm that $16$ records appear in the GuestAndWorkshop query results. Close the query, saving if necessary.