Given the Table Below,how Much Does the 13th Worker Add

Multiple Choice

Given the table below,how much does the 13th worker add to total output? $\begin{array}{cccc}\begin{array}{c}\text { Number of } \\\text { Workers }\end{array} & \begin{array}{c}\text { Total } \\\text { Product }\end{array} & \begin{array}{c}\text { Average } \\\text { Product }\end{array} & \begin{array}{c}\text { Morginal } \\\text { Product }\end{array} \\\hline 5 & -&28 & -\\10 & - & - & 30 \\15 & 420 & - &- \\20 & -& -&22 \\\hline\end{array}$

A) 28 units
B) 29 units
C) 130 units
D) 420 units
E) none of the above