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

How to clean the sheath of a horse
Understand the pros.
In general, arguments in favor of washing a horse's sheath focus on hygiene and reducing the chances of infection. Bacteria tend to colonize around the smegma.

Pick your answer from:
[i] Fortunately, many horses are so used to this stain it is less noticeable and will no longer change color. Some horses will not even feel their inner thighs if the sheath is examined after being cleaned.;
[ii] The exact nature of the secretion and the likelihood of infection vary from horse to horse. No matter what, an excessive build-up can lead to irritation and inflammation in any horse.;
[iii] Hygiene is imperative for a horse's health, but not for the health of a horse. To maintain a clean sheath, you'll want to have it cleaned every 3-4 days (or whenever your horse allows you to do so).;
[iv] In general, healthy horses wash the sheath at least two times daily with a gentle cleanser, creating less risk of germs and the materials being used ultimately increased protection against infection. However, hygiene is the virtue of keeping the sheath clean and safe.;
[ii]