Too weak. (A) tells us how policy should “generally” be designed. But it doesn’t help establish what should be done with emissions standards in this case. There might be other considerations (decreasing pollution) that could justify designing policy differently.

Starts in the wrong place and ends in the wrong place. The reasoning of the argument had nothing to do with the willingness of people to accept stricter emissions standards. And, keeping a policy in its current form doesn’t constitute the “adoption” of a policy.

Establishes a bridge from the premise to the conclusion. Rephrased, (C) tells us that if we don’t have compelling evidence that the consequences of changing a policy are better than the consequences of leaving the policy the same, then we shouldn’t change the policy. The premise establishes that we don’t have enough evidence that higher air standards would help more than the job loss from those higher standards would hurt. (C), then, allows us to conclude that we shouldn’t change the air standards.

Reaches the wrong destination. (D) dells us when governmental policy should be changed. But it doesn’t tell us when governmental policy should not be changed.

Starts at the wrong place and reaches the wrong place. Knowing that we should make a particular assumption as part of the decision-making process does not tell us what the decision should be. And, we don’t lack clear evidence of the consequences of keeping standards the same. (We lack clear evidence regarding how to weigh the consequences.)