Refer to the Following -How Much Does the 13th Worker Add to Total Output

Multiple Choice

Refer to the following:

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

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