The Diagram Below Shows the Market for Tradable Pollution Permits

The diagram below shows the market for tradable pollution permits. Figure 17- 7
-Refer to Figure 17- 7, which depicts the market for tradable pollution permits. Improvements in firms' abatement technology will be expected to

A) shift the demand curve to the left.
B) shift the supply curve to the right.
C) shift the supply curve to the left.
D) shift the demand curve to the right.
E) not have any impact on the equilibrium.