He writes "the smallest box". But the set (width, height, depth) of the dimensions of the boxes is not totally ordered. So this question makes no sense. Maybe

He writes "the smallest box". But the set (width, height, depth) of the dimensions of the boxes is not totally ordered. So this question makes no sense. Maybe he means another metric, e.g. by volume? But: - first problem, he seems to expect that people with whom he talks should not make assumptions - second problem, does he really expect the store clerk to calculate the volumes of all the boxes? I don't know, are we sure he is not actually stupid?