When the application si run, it appears as follows You need to ensure that the TextBlock control with the contents "Product shipped" is horizontal centered to the grid? Which mark up segment should you add to the TextBlock control?（）
- A GridView.Columncollection="1,2"
- B Grid.Columnspan="2"
- C Manipulation.ManipulationCharacter="2"
- D TextBlock.TextAllignment ="Center"