问题：

[单选] A Windows Communication Foundation (WCF) application uses a data contract that has several data members. You need the application to throw a SerializationException if any of the data members are not present when a serialized instance of the data contract is deserialized.What should you do?（）

A . Add the KnownType attribute to the data contract. Set a default value in each of the data member declarations.
B . Add the KnownType attribute to the data contract. Set the Order property of each data member to unique integer value.
C . Set the EmitDefaultValue property of each data member to false.
D . Set the lsRequired property of each data member to true.