C.the profit or loss associated with a unit of sale
Explanation:
The economics of one unit is a calculation of the profit or loss associated with a unit of sale. This option fits because it's subtracting the variable expense for the unit and the loss, therefore its ''<em>C'</em>'.
Answer A:The Electoral College potentially throws off the balance established in the legislative branch by the Constitution. Answer B:No, because it explains how the legislative branch creates balance under the Constitution.
