The diagram illustrates the cost and benefit curves for a good in a free market. Which combination is correct?
- Aactual output P1Q1; social optimal level of output P3Q3
- Bactual output P2Q2; social optimal level of output P3Q3
- Cactual output P2Q2; social optimal level of output P4Q4
- Dactual output P3Q3; social optimal level of output P4Q4