Which word is an interjection?

Ouch! That thorn on the rosebush scratched my finger and my wrist.

A.

on

B.

Ouch

C.

and

D.

that

The word B) Ouch is an interjection.

An interjection is a word used to indicate an emotion (also an exclamation). Some cases of expressing discomfort would be words such as 'ouch' or 'ow'. Examples of words expressing greeting would be 'hello' or 'hi'. Interjections are commonly followed by a comma mark, but not all have to be.

Ouch would be the interjection because it is an explanation of pain, a sudden statement.