Answer the following question given this paragraph: 

What is one of the most important characteristics of a referee? A referee must be neutral. He can’t favor one team over the other. In chemistry, being neutral means not being an acid or a base. Pure water is an example of a neutral substance. In some chemical reactions, an acid and a base combine to form neutral products, including water. You’ll see how this happens when you read this article.


Q: What do you call a substance that is not an acid or a base?

 Choices:

- equivalent

- toxic

- oxidic

- neutral

A:
neutral
