D. Mississippi because onomatopoeia is when the word is the same as the meaning. boom means boom, pew means pew, cackle means cackle. Basically onomatopoeia is sounds
I had put the answer on a ScreenShot, so you can see what part is what.(I hope this helps you! Feel free to message me if you have any further questions :) Have a nice day!!)
To pretect the brain so people don't get brain damage