In the United States proven oil reserves—the amount of oil considered extractablefrom known fields—are at the same level as they were ten years ago. Yet over thissame period no new oil fields of any consequence have been discovered, and the annual consumption of domestically produced oil has increased. Which one of the following, if true, best reconciles the discrepancy described above?

(A) Over the past decade the annual consumption of imported oil has increased more rapidly than that of domestic oil in the United States.

(B) Conservation measures have lowered the rate of growth of domestic oil consumption from what it was a decade ago.

(C) Oil exploration in the United States has slowed due to increased concern overthe environmental impact of such exploration.

(D) The price of domestically produced oil has fallen substantially over the past decade.

(E) Due to technological advances over the last decade, much oil previously considered unextractable is now considered extractable.