单选题 What caused the appearance of the "gray culture" phenomenon?

A、 An increasing proportion of older people within the total population.
B、 Older people are regarded as important consumers of leisure goods and services.
C、 Some sociologists have begun to study the cultural implications of an aging population.
D、 All of the abov

【正确答案】 D

【答案解析】第一段阐述了grey culture出现的原因，包括：老年人口represent an increasing proportion within the total population，老年人口are increasingly regard as important consumers，一些社会学家也开始analyze the cultural implications of population aging，选项A，B，C的内容均符合。