The correct answer is onomatopoeia.
The word wail can have several meanings, but all of them have to do with sounds. If you wail, you produce a high-pitched cry, because you are sad or in pain.
Onomatopoeia is a figure of speech where a word can express the sounds coming from nature. So, when you wail, you produce a particular sound, which is why this is onomatopoeia.
