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: 1). 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.; 2). 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.; 3). 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.; 4). 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.;
4).