The Diagram Below Shows the Marginal Cost of Pollution Abatement

The diagram below shows the marginal cost of pollution abatement for two firms, Firm X and Firm Y. FIGURE 17- 4
-Refer to Figure 17- 4. Firms X and Y have an emissions tax of $t imposed on each unit of pollution they produce. If Firm X chooses to abate QX units of pollution, the total cost of its abatement is

A) tax amount t multiplied by the level of pollution abatement, QX.
B) area beneath the marginal cost of pollution abatement curve.
C) area below the horizontal line at t and above the MC of pollution abatement curve.
D) area beneath the marginal cost of pollution abatement curve up to QX.
E) tax amount t multiplied by the maximum possible level of pollution abatement.