To model the effects of a carbon tax on CO2 emissions, policymakers study the marginal cost of

Question:

To model the effects of a carbon tax on CO2 emissions, policymakers study the marginal cost of abatement B(x), defined as the cost of increasing CO2 reduction from x to x + 1 tons (in units of 10,000 tons— Figure 4). Which quantity is represented by the area under the curve over [0, 3] in Figure 4?

100 75 50 25 B(x) ($/ton) 1 2 Tons reduced (ten thousands) 3 -X