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. 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))]