Refer to the Following:
Amount of Total Output Produced from Various

Multiple Choice

Refer to the following:
Amount of total output produced from various combinations of labor and capital.

$\begin{array}{cccc} &\text { Units of Capital }\\&& 1 & 2 & 3 \\\hline &1 & 80 & 100 & 120 \\\text {Units }&2 & 180 & 220 & 260 \\\text {of }&3 & 270 & 330 & 390 \\\text {Labor }&4 & 340 & 420 & 500 \\&5 & 390 & 490 & 590 \\&6 & 410 & 530 & 650\end{array}$
-If labor is fixed at three units, how much does the third unit of capital add to total output?

A) 60
B) 80
C) 110
D) 130
E) none of the above