You are designing a Windows Phone 7 application. The application must use a dynamic application key to access a companys web services. You need to recommend a way to help keep the application secure. What should you recommend?

A.
Create a proxy web service to retrieve the application key.

B.
Store the application key in a resource file associated to the application project.

C.
Encrypt the application key and store it in the Application.Resources section of the App.xaml.cs file.

D.
Use a custom class in the same assembly as the WebClient object that contains a string property holding the application key.