Utrania was formerly a major petroleum exporter, but in recent decades economic stagnation and restrictive regulations inhibited investment in new oil fields. In consequence, Utranian oil exports dropped steadily as old fields became depleted. Utrania' s currently improving economic situation, together with less-restrictive regulations, will undoubtedly result in the rapid development of new fields. However, it would be premature to conclude that the rapid development of new fields will result in higher oil exports, because __. Which of the following most logically completes the argument? ['new technology is available to recover oil from old oil fields formerly regarded as depleted', 'the improvement in the economic situation in Utrania is expected to result in a dramatic increase in the proportion of Utranians who own automobiles', 'the price of oil is expected to remain relatively stable over the next several years', 'most of the investment in new oil fields in Utrania is expected to come from foreign sources']