-Refer to the Above Figure $\mathrm { P } _ { 5 }$

-Refer to the above figure.If the government requires the natural monopolist to charge the efficient price,it will charge price

A) $\mathrm { P } _ { 5 }$ and sell
$\mathrm { Q } _ { 1 }$ units.
B) $P _ { 2 }$ and sell
$\mathrm { Q } _ { 1 }$ units.
C) $\mathrm { P } _ { 3 }$ and sell
$\mathrm { Q } _ { 3 }$ units.
D) $P _ { 1 }$ and sell
$\mathrm { Q } _ { 4 }$ units.