Option 1: Suitable -> means appropriate or fitting; not an opposite of repulsive.
Option 2: Disgusting -> actually a synonym (similar meaning) of repulsive, not an antonym.
Option 3: Critical -> means expressing disapproval; unrelated to the concept of being repulsive.
Option 4: Appealing -> means attractive or pleasant; directly opposite to repulsive.
Hence, Option 4: Appealing -> Repulsive means causing disgust or being highly unpleasant, while appealing means attractive or pleasing, making them perfect antonyms -> correct