If the marginal cost for reducing CO2 emissions is $5 per 5-ton increments (such that it would be $5 for the first 5 tons, then $10 for the second 5 tons, then $15 for the third 5 tons, and so on), what is the total cost for reducing CO2 emissions by 25 tons? A) $125 B) $75 C) $25 D) $5