单项选择题

Like a lot of carless New Yorkers, I am generally confused by bursts of populist outrage over high gas prices. But I have always assumed that the anger is genuine. But amid the recent mania over prices hitting $4 a gallon, I decided to figure out whether this fury is economically rational. So I took a look at data from the Census Bureau, which conducts a quarterly survey of American spending habits. During these last few years of historically high oil prices, Americans spent about $40 a week, or $2,000 a year, on gas. That"s around 5 percent of our overall spending. It"s less than half of what we spend on restaurants and entertainment.
High gas prices must be forcing Americans to cut back in other ways, right That"s what the economist Lutz Kilian at the University of Michigan wondered. He looked at personal spending habits during periods of high energy prices and discovered that "somewhat surprisingly, there is no significant decline in total expenditures on recreation," which was one place they expected to find frugality. In other words, Americans may protest loudly, but their economic behavior indicates a remarkable indifference to the price of oil.
While sustained high gas prices would certainly produce some turmoil, so would potential spikes in countless other globally traded commodities. But there"s a reason populist outcries don"t start around soybean prices or magnesium spikes. Oil is the only volatile commodity that most Americans deal with directly: we are buffered from most other price swings by our relative wealth. Unlike people in poor countries, consumers here don"t generally buy raw commodity foods; we buy our meals processed or prepared. With most goods, the commodity price has even less impact on cost. "When people buy a phone," Kilian says, "they don"t buy the copper that makes the wiring."
With gas, though, hurtling prices are unavoidable. Every day, U. S. drivers pay a price determined by forces all over the world that are hard to understand and harder for the United States to control. Even if we invested in better refineries and exploited every possible energy source, from the Keystone pipeline to the Alaskan wilderness, the impact could be minimal. It could eventually lower prices at the pump—but only if nothing else affects them, like OPEC lowering its production to drive prices back up again. The price of oil is, of course, affected by hundreds of interrelated factors.
Many analysts I"ve spoken with suggest that oil prices should fall fairly soon. This will be welcome news to the less-fortunate American families who are not impervious to the price at the pump and to anyone who claims to be pinching pennies because of gas. But as unpopular as it may sound, the best possible future for most Americans may involve much higher gas prices. As billions of people, throughout the world, enter the middle class in the coming decades, there will be an enormous increase in the demand for gas. This, along with rising environmental considerations, is likely to send the prices far higher than they are today. The word "impervious" in Paragraph 5 is closest in meaning to ______.

A.immune
B.implicit
C.impressionable
D.imprudent