(CO 2) Which of the following information on database relationships is true?

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There are two tables shown. Order Details and Orders. Keys and attributes are listed. The Order Details table is connected with a line that has a "Many" symbol on the left and a "1" on the left connection. Order Details has a key next to OrderID and ProductID with attributes of UnitPrice, Quantity, and Discount. The Orders Table has a a key next to OrderID with additional attributes of: CustomerID, EmployeeID, OrderDate, RequiredDate, ShipVia, Freight, ShipName, ShipAddress, ShipCity, ShipRegion, ShipPostalCode, and ShipCountry.

A. A unique field cannot be used.

B.No primary key is necessary to build a relationship.

C. For a database relationship to exist, one table must have a primary key, and the second table has a matching foreign key.

D A database can exist without relationships.