Refer to the Following -The Maximum Amount That Can Be Produced Using 20 Workers

Refer to the following:

$\begin{array}{cccc}\begin{array}{c}\text { Number of } \\\text { Workers }\end{array} & \begin{array}{c}\text { Total } \\\text { Product }\end{array} & \begin{array}{c}\text { Average } \\\text { Product }\end{array} & \begin{array}{c}\text { Marginal } \\\text { Product }\end{array} \\\hline 5 &- & 28 & -30 \\10 & - & - & 30\\15 & 420 & - &- \\20 &- & - &22\\\end{array}$
-The maximum amount that can be produced using 20 workers is

A) 442 units.
B) 530 units.
C) 22 units.
D) 420 units.
E) 26.5 units.