That is either the iPhone 4 or 4S. All other devices are eliminated due to design conflicts. I.E. iPod Touch does not have a metal antenna band around it, iPhone 5 has the headphone jack on the bottom, etc.
It's a white iPhone 4. The iPhone 4S has an antenna insulating spacer between the ring/vibrate switch and the top of the phone. The phone in the picture doesn't have this so it has to be the iPhone 4.