Use the Following General Linear Supply Function $Q _ { 5 } = 40 + 6 P - 8 P _ { I } + 10 F$

Use the following general linear supply function: $Q _ { 5 } = 40 + 6 P - 8 P _ { I } + 10 F$ where $Q _ { 5 }$ 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.Suppose $P _ { I }$ = $40 and F = 50,what is the lowest price that will induce firms to supply 400 units of output?

A) $15
B) $20
C) $25
D) $30
E) $35