-In the Above Figure,the Optimal Level of Pollution Cleanup Is $\mathrm { Q } _ { 1 }$

-In the above figure,the optimal level of pollution cleanup is

A) $\mathrm { Q } _ { 1 }$ .
B) Q₂.
C) $\mathrm { Q } _ { 3 }$ .
D) $\mathrm { Q } _ { 4 }$ .