In my economics class, I was given this graph as a practice question, and was told to solve it. I tried to do it on my own, but I have no idea how to read it, and can't figure out the answer.

Can someone explain it?

Select one: O a. 10 MTCO2 O b. 20 MTCO2 O c. 30 MTCO2 O d. 5 MTCO2 O e. 15 MTCO2 Of. 45 MTCO2 O g. 35 MTCO2 O h. 40 MTCO2 O i. 25 MTCO2 CheckQ: Using the figure below, how many MT (metric tonnes) of CO2 (carbon dioxide) equivalent will this firm reduce if pollution charges are $3,600 per metric tonne? Marginal Cost / MTCO2 eq. $8,000 $7,000 $6,000 $5,000 Cost / MTCO2 $4,000 $3,000 $2,000 $1,000 5 10 15 20 25 30 35 40 45 50 55 Quantity of Metric Tonnes of Carbone Dioxide Equivalent