Multi-choice problem: Continue writing the next sentence in this paragraph:

How to train a horse to lead
Get a nice soft halter.
If you are teaching a young, you must first teach it to wear a halter. The halter (sometimes known as the headcollar) is the harness that you will place over the horse's head, around the muzzle and up over the poll and ears.

Choices:
A). Halter and head-collars are a good way to teach a horse to lead. Allow your horse to stand but not to sit if this is the first time riding in a horse arena..
B). You can purchase halter styles that tend to work for you. Most orders nowadays claim to require a large size halter, but no regard for this is in dispute..
C). You can purchase either a halter and a helmet or attach them to the bridle. A helmet is important for teaching a horse to lead and exerting pressure when doing so..
D). You can buy these at any horse supply or tack store, or you can always find one online. Make sure you buy a soft halter, since hard poor quality nylon will rub and can cause sores on your horse's sensitive skin..
D).