Modifier Keys:A modifier key is a key on a computer's keyboard that is only used in conjunction with another key. Modifier keys are often used with other keys to perform computer keyboard shortcuts and other commands. For example, in many text editor programs pressing the Ctrl+A selects all text. Examples of modifier keys:On an IBM compatible computer, modifier keys include Alt, Ctrl, Shift, and the Windows key. On the Apple Macintosh computer, the Control, Option, Command, and Shift keys are modifier keys. Additionally, most laptop and some desktop keyboards contain an Fn modifier key. Therefore, option 2 is the correct answer.