Concept:Prepositions show the relationship between a noun and another word. 'At' indicates a specific point or location.Explanation:The sentence tells where the kitchen is located. "The back of the house" is a precise place. 'At' is correct for a specific point. 'In' would mean inside the house, but the back is outside. 'About' means approximately or regarding. 'Of' shows belonging or relationship. Neither fits here.Answer:D. at