This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to post while trotting on a horse
Understand why posting is done.
The main reason to post while riding is to avoid being jostled around in the saddle during a particularly bumpy gait-the trot. This makes things more comfortable for the rider and is easier on the horse's back.

Choose your answer from:
--Keep the saddle in a safe place. This can be intended to prevent discomfort during canter, and can also slow the horse if the gait is too steep, because it involves requiring extra support.
--Once you become more experienced with the rising trot, it is also possible to change the horse's rhythm simply by posting more quickly or slowly. The horse will alter his rhythm to match with your own, thus sometimes eliminating the need for hand and leg signals.
--Apply both reins in the stirrup until the other rein is tightened, then hold them. The step-to-trot method is best for trotting.
--It can be useful to have your horse cool off. If you feel like you're jarring the horse and causing any discomfort then posting may be the best thing to do.
The answer is:
Once you become more experienced with the rising trot, it is also possible to change the horse's rhythm simply by posting more quickly or slowly. The horse will alter his rhythm to match with your own, thus sometimes eliminating the need for hand and leg signals.