-Refer to the Above Figure $P _ { 1 }$ And $\mathrm { Q } _ { 1 }$

-Refer to the above figure.What is the socially optimal point of production?

A) $P _ { 1 }$ and
$\mathrm { Q } _ { 1 }$ .
B) $\mathrm { P } _ { 4 }$ and
$\mathrm { Q } _ { 1 }$ .
C) $P _ { 1 }$ and
$\mathrm { Q } _ { 4 }$ .
D) $\mathrm { P } _ { 3 }$ and
$\mathrm { Q } _ { 2 }$ .