The correct answer is C. Handled.
The Handled property of the e parameter is used to cancel the key if not accepted in the text area. If the Handled property is set to true, the keystroke will not be processed.
The Remove and RemoveChar properties are used to remove characters from the text area. The Remove property removes the character at the specified index, while the RemoveChar property removes the character that was just entered.
The handled property is a boolean value that indicates whether the event was handled by the control. If the event was handled, the value of the handled property will be true. If the event was not handled, the value of the handled property will be false.
Here is an example of how to use the Handled property to cancel a keystroke:
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Escape)
{
e.Handled = true;
}
}
In this example, the KeyDown event handler checks to see if the Escape key was pressed. If it was, the Handled property is set to true, which cancels the keystroke.