$Q _ { s } = 40 + 6 P - 8 P _ { I } + 10 F$

$Q _ { s } = 40 + 6 P - 8 P _ { I } + 10 F$ where $Q _ { s }$ is the quantity supplied of the good, P is the price of the good, $P _ { I }$ is the price of an input, and F is the number of firms producing the good.
-If $P _ { I }$ = $20 and F = 60 what is the equation of the supply function?

A) $Q _ { s } = 400 + 6 P$
B) $Q _ { 5 } = 40 + 8 P$
C) $P = 480 + 6 Q _ { 5 }$
D) $Q _ { s } = 480 + 6 P$
E) none of the above