Answer:
Odd answer choices, but I would put "It shows you that water is a reversible reaction, which contains hydrogen and hydroxide reactions."
Step-by-step explanation:
The first choice is weird, although water can be written as HOH that doesn't help you understand acids and bases.
The third choice doesn't do that either, and there are more ways for water to be formed than that.
The second choice helps you understand acids and bases, specifically, in water's self-ionization process. It also shows you that it is neutral because it is formed from Hydrogen, which is usually present in acids, and a Hydroxide group, which is usually present in bases.