The correct answer is D. MessageBox.Show.
MessageBox.Show is a method in the System.Windows.Forms namespace that displays a message box. It takes three parameters: the text of the message, the type of message box, and the buttons that should be displayed.
The type of message box can be one of the following values:
- MessageBoxButtons.OK: A button that says “OK”.
- MessageBoxButtons.OKCancel: Two buttons, “OK” and “Cancel”.
- MessageBoxButtons.YesNo: Two buttons, “Yes” and “No”.
- MessageBoxButtons.YesNoCancel: Three buttons, “Yes”, “No”, and “Cancel”.
The buttons that are displayed can be specified as a bitmask. For example, to display the “OK” and “Cancel” buttons, you would use the value MessageBoxButtons.OKCancel.
The following code shows how to display a message box with the text “Hello, world!” and the “OK” button:
MessageBox.Show("Hello, world!", MessageBoxButtons.OK);
The following code shows how to display a message box with the text “Are you sure you want to delete this file?” and the “Yes”, “No”, and “Cancel” buttons:
MessageBox.Show("Are you sure you want to delete this file?", MessageBoxButtons.YesNoCancel);