Comparing the Arduino Uno and the Nano, you'll notice that the ... To use it as such, you need a USB cable and a 5V power ...

and its USB port is somewhat outdated (who still has a USB-B cable nowadays?). But even after eliminating the Uno from your selection, you'll still be left with a wide array of Arduino boards to ...

He’s using an Arduino Uno and an Ethernet breakout board to hook it up to the network. This allows him to send text messages to himself when the alarm system is armed, disarmed, or triggered.