According to the Findings of a Study Reported in the Case

According to the findings of a study reported in the Case in Point titled "Trading Pollution Rights," when the tradable permit approach was used:

A) goals for reduced emissions were achieved at costs lower than had been projected.
B) goals for reduced emissions were achieved, but the costs were higher than had been projected.
C) emissions increased, but the marginal cost of emissions went down.
D) emissions decreased, but the marginal cost of abatement was higher than expected.