[单选题]消费可能线的位置和斜率取决于
A.消费者的收入
B.消费者的收入和商品价格
C.消费者的偏好
D.消费者的偏好、收入和商品价格

问：

俺知道在中国的历史上许多皇帝、大官或有权势的人都养过男宠，比如汉武帝……

那么，至今为止，国内考古中难道难道没有发现过类似的证据？

（不包括一般文献记载，比如史记、汉书之类的，因为这些我都看过了……

 只算陪葬，墓，明器之类）

One answer to the question of land shortage was suggested by an organization some years ago. A city was to be built at sea, housing 30,000 people.
The suggestion was to shape the city like a harbor (港口). The outer wall of the harbor would stand on steel columns resting on the sea bed. Naturally this could only be where the water was fairly shallow. The people would like to live in flats in the fifty-metre high outer wall. The flats would be all face inwards, and would be made of concrete (混凝土) and glass. The glass would be specialy made and colored to control the heat and strong light from the sun. The planners called this man-made harbor would be calm. It would be floating islands carrying more building; a hospital, two theaters, museums, an art exhibition hall and a church. One of the islands would be a special factory to take the salt out of sea water and turn it into fresh water.
People living in the city could move around on small boats driven by elec
A. there is not enough space for building cities on land
B. land transportation has become increasingly difficult
C. there are too many people on land
D. present cities are heavily polluted by cars