Which of the following is NOT about etiquette?
选项：

A:At table, while eating he would not speak. When in bed he would not talk.(食不语，寝不言）;
B:When at a public dinner in his native place, he would always leave the table as soon as the old people left.（乡人饮酒，仗者出，斯出矣。）;
C:“Have you eaten yet?” is the way a Chinese greets an acquaintance.;
D:The prosperity of a nation is not only the prosperity of economic strength, but also the prosperity of the nation’s culture.