Consider the Following Production and Cost Schedule for a Firm

Consider the following production and cost schedule for a firm. $$\begin{array}{l}\begin{array} { | l | l | l | l | } \hline \begin{array} { l } \text { Total Number of } \\\text { Units of the } \\\text { Factor }\end{array} & \begin{array} { l } \text { Total Number of } \\\text { Units of Output }\end{array} & \begin{array} { l } \text { Price per Unit } \\\text { of Output }\end{array} & \begin{array} { l } \text { Total Cost } \\\text { of Production }\end{array} \\\hline 10 & 30 & \$ 10 & \$ 100 \\\hline 11 & 44 & \$ 10 & \$ 110 \\\hline 12 & 64 & \$ 10 & \$ 120 \\\hline 13 & 78 & \$ 10 & \$ 130 \\\hline 14 & 84 & \$ 10 & \$ 140 \\\hline 15 & 86 & \$ 10 & \$ 150 \\\hline\end{array}\\\text { TABLE 13- } 1\end{array}$$
-Refer to Table 13- 1. How many units of this factor of production would the profit- maximizing firm hire if the price of each unit of the factor was $30?

A) 13
B) 15
C) 12
D) 14
E) It is not possible to determine with the data given.