下图反映的是在一定时期内M商品的供求量（Q轴）随价格（P轴）变化的情况。曲线D为需求曲线，S为供给曲线，E为M商品的均衡价格。假定其他条件不变，下列关于均衡价格E变动的描述正确的是

①当居民当前可支配收入增加时，会导致均衡价格E→E₁ 

②当居民预期未来收入不确定时，会导致均衡价格E→E₁

③当M商品预期未来价格上涨时，会导致均衡价格E→E₂

④当M商品互补商品价格上涨时，会导致均衡价格E→E₂

A．①②

B．②③

C．③④

D．①④

In science the meaning of the word "explain" suffers with civilization’s every step in search of reality. Science cannot really explain electricity, magnetism, and gravitation; their effects can be measured and predicted, but of their mature no more is known to the modem scientist than to Thales who first speculated on the electrification of amber. Most contemporary physicists reject the notion that man can ever discover what these mysterious forces "really" are. "Electricity," Bertrand Russell says, "is not a thing, like St. Paul’s Cathedral: it is a way in which things behave. When we have told how things behave when they are electrified, we have told all there is to tell." Until recently scientists would have disapproved of such an idea. Aristotle, for example, whose natural science dominated Western thought for two thousand years, believed that man could arrive at an understanding of reality by reasoning from self-evident principles. He felt, for example, that it is a self-evident principle that everything in the universe has its proper place, hence one can deduce that objects fall to the ground because that’s where they belong, and smoke goes up because that’s where it belongs. The goal of Aristotelian science was to explain why things happen. Modem science was born when Galileo began trying to explain how things happen and thus originated the method of controlled experiment which now forms the basis of scientific investigation.

Which of the following principles most influenced scientific thought for two thousand years

A．The speculations of Thales.

B．The forces of electricity, magnetism, and gravity.

C．Aristotle’s natural science.

D．Galileo’s discoveries.