Which of the following refers to persons, things, places, or animals?

A noun is a part of speech in the English grammar that refers to a person, place, animal, idea, feeling, thing, etc. E.g. (Paris, tiger). A verb refers to an action or doing of something (like running, eating). Articles refer to "a", "an", and "the"- they are used before a noun to show if it's specific or general. (Eg. An apple, A ball, The Moon). Hence, A is the correct option.