Answer the Question on the Basis of the Following Marginal

Multiple Choice

Answer the question on the basis of the following marginal product data for resources a and b.The output of these independent resources sells in a purely competitive market at $1 per unit. $\begin{array}{ccc}\begin{array}{ccc}\text { Inputs } \\\text { of a } & & \mathrm{MP}_{\mathrm{a}} \\\hline1 & & 25 \\2 & & 20 \\3 & & 15 \\4 & & 10 \\5 & & 5 \\6 & & 2 \\7 & & 1\end{array}\begin{array}{c}\begin{array}{c}\text { Inputs } \\\text { of } b\end{array} & & M P_{b} \\\hline1 & & 40 \\2 & & 36 \\3 & & 32 \\4 & & 24 \\5 & & 20 \\6 & & 16 \\7 & & 8\end{array}\end{array}$ Refer to the given data.Assuming the prices of resources a and b are $5 and $8 respectively,when the firm hires the profit-maximizing combination of resources,its economic profit will be:

A) $170.
B) $76.
C) $145.
D) $138.