You are designing a Windows Phone 7 application. Every three hours the application must change the application tile to show a picture depending on the current weather conditions. The application must perform this independently and without outside influence. You need to ensure that the application tile is updated every three hours. Which class should you recommend?

A.
BindToShellTile

B.
HttpWebRequest

C.
ShellTileSchedule

D.
PhoneApplicationService