Which of the following equations describes a trade surplus?

The marginal cost of labor, MCL, is defined as the

A) total cost of producing a certain amount of output. B) total cost of hiring an additional worker. C) additional cost of hiring an additional worker. D) additional fixed cost of producing an additional unit of output.

Suppose capital and labor are perfect substitutes resulting in a production function of q = K + L. That is, the isoquants are straight lines with a slope of -1

Derive the long-run total cost function TC = C(q) when the wage rate is w and the rental rate on capital is r.