How do you know if a device is an input device or an output device?

a$)$ An input device includes speakers, headphones, and interactive whiteboards. An output device includes game controllers and webcams.

b$)$ An input device is how the processed information is displayed. An output device enters data and instructions into the memory of the device.

c$)$ An input device creates formats in text, graphics, audio, video, or any combination of these. An output device is a touchscreen or keyboard.

d$)$ An input device enters data and instructions into the memory of the device. An output device is how the processed information is displayed.