🎴 Flashcard Mode

To answer this question, the user needs to have knowledge about the ways to activate a Button control in a Windows Forms application.

Option A is correct. A Button control can be activated programmatically by calling its Click event.

Option B is correct. A Button control can be activated by clicking on it with the mouse.

Option C is correct. A Button control can be activated by setting the form's DefaultButton property to the Button control that should be activated when the user presses the Enter key.

Therefore, option D is correct since both option A and B are correct.

Option E is incorrect since it is not necessary to use all three methods to activate a Button control.

Therefore, the answer is: D.