【单选题】
You are developing a Windows Communication Foundation (WCF) service that contains the following service contract.[ServiceContract（ ）]public interface IPaymentService{ [OperationContract（ ）] void RecordPayments(Person person);}public class Person{ ... }public class Employee : Person{ ... }public class Customer : Person{ ... }You need to ensure that RecordPayments can correctly deserialize into an Employee or a Customer object.<br /> What should you do?（）
A、Add the following KnownType attribute to the Employee class and to the Customer class. [KnownType(GetType(Person))]
B、Implement the IExtensibleDataObject interface in the Person class.
C、Implement the IExtension(ofType(T)) interface in the Person class.
D、Add the following KnownType attributes to the Person class. [KnownType(GetType(Employee))] [KnownType(GetType(Customer))]
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