GRE Reading Comprehension: ETS-GRE阅读ETS - 0XUYCS7214WYJFI27

It can be inferred from the passage that the availability of temperature-depth records for any specific area in the United States depends primarily on the A. possibility that HDR's may be found in that area B. existence of previous attempts to obtain oil or gas in that area C. history of successful hot water or steam recovery efforts in that area D. failure of inhabitants to conserve oil gas reserves in that area E. use of coal as a substitute for oil or gas in that area