Option 1 -> "Gloomy" means dark or causing sadness, not the same as causing horror.
Option 2 -> "Greasy" means oily or slippery, completely unrelated despite sounding similar.
Option 3 -> "Disgusting" means causing revulsion or strong disapproval, which closely matches grisly's meaning.
Option 4 -> "Boorish" means rough-mannered or coarse, not related to something horrifying.
Hence, Option 3: Disgusting -> "Grisly" describes something gruesome, horrifying, or causing horror and disgust (like a grisly crime scene), making "disgusting" the best match among the given options -> correct