Consider the Following Table for a Firm TABLE 13- 2
-Refer to Table 13- 2

Consider the following table for a firm.The first column shows the number of units of a variable factor of production employed by the firm. $$\begin{array} { | c | l | } \hline \begin{array} { c } \text { Total Number of } \\\text { Units of the Factor }\end{array} & \begin{array} { c } \text { Total Number of } \\\text { Units of Output }\end{array} \\\hline 2 & 100 \\\hline 3 & 110 \\\hline 4 & 128 \\\hline 5 & 148 \\\hline 6 & 162 \\\hline 7 & 170 \\\hline 8 & 166 \\\hline\end{array}$$ TABLE 13- 2
-Refer to Table 13- 2.Suppose the firm is a perfect competitor and faces a given price of the product equal to $2 per unit.The marginal revenue product of the 5th unit of the factor is

A) $40.
B) $128.
C) $20.
D) $148.
E) $2.