Answer the Question on the Basis of the Following Demand $\quad$

Answer the question on the basis of the following demand and cost data for a specific firm. $\quad$$\quad$$\quad$$\quad$$\text { Demand Data }$ $\quad$$\quad$$\quad$ $\text { Cost Data }$
$\begin{array}{|c|c|c|c|c|}\hline&&(3) &\text { Total } \\\text { (1) } & \text { (2) } & \text { Quantit } & \text { Output } & \text { Total } \\\text { Price } & \text { Price } & \text { Y} & & \text { Cost }\\\hline \$ 50 & \$ 35 & 2 & 2 & \$ 45 \\\hline 45 & 30 & 3 & 3 & 55 \\\hline 40 & 25 & 4 & 4 & 70 \\\hline 35 & 20 & 5 & 5 & 90 \\\hline 30 & 15 & 6 & 6 & 115 \\\hline 25 & 10 & 7 & 7 & 145 \\\hline 20 & 5 & 8 & 8 & 180 \\\hline\end{array}$ If columns 1 and 3 are this firm's demand schedule, the profit-maximizing level of output will be

A) 3 units.
B) 4 units.
C) 5 units.
D) 6 units.