Refer to Table 2-3. Which of the following combinations of corn and rice is not currently attainable but would be attainable if there was an improvement in overall production technology?

A) 2,000 bushels of corn and 300 bushels of rice
B) 1,500 bushels of corn and 900 bushels of rice
C) 1,250 bushels of corn and 1,700 bushels of rice
D) 500 bushels of corn and 1,700 bushels of rice

Given that the combination is not currently attainable but would be with an improvement in technology, it suggests that this combination requires more resources or technology than currently available. Choices A, B, and D are likely within the current production possibilities, implying that choice C is beyond current capabilities but could be reached with technological advancements.