Refer to the Following:
a Short-Run Production Function Was Estimated $Q = - 0.002 L ^ { 3 } + 0.16 L ^ { 2 }$

Multiple Choice

Refer to the following:
A short-run production function was estimated as

$Q = - 0.002 L ^ { 3 } + 0.16 L ^ { 2 }$
-At what level of labor usage does the maximum average product occur?

A) 20
B) 30
C) 40
D) 50
E) 60