You are creating a Windows Communication Foundation (WCF) service that accepts messages from clients when they are started. The message is defined as follows:[MessageContract] public class Agent { public string CodeName { get; set; } public string SecretHandshake { get; set; }}You have the following requirements: The CodeName property must be sent in clear text. The service must be able to verify that the property value was not changed after being sent by the client. The SecretHandshake property must not be sent in clear text and must be readable by the service.What should you do?（）

A. Add a MessageBodyMember attribute to the CodeName property and set the ProtectionLevel to Sign. Add a MessageBodyMember attribute to the SecretHandshake property and set the ProtectionLevel to EncryptAndSign.
B. Add a DataProtectionPermission attribute to the each property and set the ProtectData property to true.
C. Add an xmlText attribute to the CodeName property and set the DataType property to Signed. Add a PasswordPropertyText attribute to the SecretHandshake property and set its value to true.
D. Add an ImmutableObject attribute to the CodeName property and set its value property to true. Add a Browsable attribute to the SecretHandshake property and set its value to false.