Two Companies, Dirty Inc

Multiple Choice

Two companies, Dirty Inc. and Filthy Inc., each of which has access to 5 different production processes, each of which has a different cost and produces a different amount of pollution. The daily costs of the processes and the number of tons of smoke emitted are shown in the table below.  
Suppose pollution is initially unregulated. If the City Council imposes a tax of $91 per day on each ton of smoke emitted, then what will be the total cost to society of the resulting reduction in pollution?

A) $90
B) $180
C) $270
D) $360