The Following Table Shows the Total Revenue and Total Cost

Multiple Choice

The following table shows the total revenue and total cost (in dollars) from different sales volumes of the good.
Table 2-1
$\begin{array} { | c | c | c | c | } \hline \text { Price } & \text { Quantity } & \text { Total Revenue } & \text { Total Cost } \\\hline 15 & 1 & 15 & 3 \\\hline 14 & 2 & 28 & 7 \\\hline 13 & 3 & 39 & 12 \\\hline 12 & 4 & 48 & 18 \\\hline 11 & 5 & 55 & 25 \\\hline 10 & 6 & 60 & 33 \\\hline\end{array}$

-Refer to Table 2-1. What is the marginal profit of the firm from the sale of the 3rd unit of the good?

A) $9
B) $6
C) $2
D) $5
E) $21