Concept:The idiom "easy on the eye" means something is pleasant or pleasing to look at.Explanation:The phrase "easy on the eye" describes something visually appealing.Among the given options, "attractive" best matches this meaning."Grandiose" means impressive or magnificent in size, "cool" means fashionable or calm, and "expensive" means costly. None of these fit the idiom as well as "attractive".Answer:C. attractive