You are creating a Windows component by using the .Net Framework 3.5.the component will be used in Microsoft Word 2007 by using a ribbon button.The component is used for uploading files. You find that Word 2007 becomes non-responsive during the upload. You need to ensure that the application completes the upload efficiently. What should you do？（）

A. Use the AsyncResult.SyncProcessMessage method.
B. Call the BeginInvoke method， perform the upload， and then call the EndInvoke method
C. Retrieve a WaitHandle from an implementation of the IAsyncResult interface before the upload.
D. Set the IsCompleted property on an implementation of the IAsyncResult interface before the upload.