Powering Arduino Nano

I will need to power an Arduino Nano (Rev 3.0) with an external 24V DC power supply ( not through the USB port), so I was wondering what I should do.

I have three possible solutions:

  1. Connect the 24V power supply to a 24V-to-12V DC buck converter, and supply the 12V voltage to the Vin pin on Arduino Nano to power my Arduino Nano.

  2. Connect the 24V power supply to a 24V-to-12V DC buck converter, and supply the 12V voltage to a voltage regulator (LM7805), and supply the 5V voltage to the 5V pin on Arduino Nano to power my Arduino Nano.

  3. Connect the 24V power supply to a voltage regulator (LM7805) directly, and supply the 5V output voltage to the 5V pin on Arduino Nano to power my Arduino Nano.

Do all of the 3 solutions work theoretically? Which one is better?