Which animal was used to move the 'toothed wheel'?

Bullocks are considered good draught animals meaning they can be used as a good source of energy and power. They moved the 'toothed wheel' of the water arrangement setup which in turn moved the garland of pots which lifted water from the wells and deposited it in a reservoir and from there it was transported to different parts of the fort through clay pipes. The other animals given as options do not have much draught power.