Explanation
The JavaScriptSerializer Class Provides serialization and deserialization functionality for AJAX-enabled applications.
The JavaScriptSerializer class is used internally by the asynchronous communication layer to serialize and deserialize the data that is passed between the browser and the Web server. You cannot access that instance of the serializer. However, this class exposes a public API. Therefore, you can use the class when you want to work with JavaScript Object Notation (JSON) in managed code.
Incorrect:
Not B, not C: The NetDataContractSerializer works with XML, but not with JSON.
Reference: JavaScriptSerializer Class
https://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer(v=vs.110).aspx