I will go with (c) for the following reason:
Question is asking for support for the following conclusion:
The reluctance of the United States automobile industry to pursue the development of new fuel-efficent technologies could threaten the industryâ€™s future.
(c)'s conclusion tells that automakers outside U.S. have slowed the
the introduction of fuel-efficient technologies but have pressed ahead with research and development of them in preparation for a predicted rise in world oil prices.
Ideally it would have been firmer if (c) had referenced that the non-US automakers have not been investing in new fuel-efficent technologies.
Any thoughts on this?
We can crack the exam together