Which one of the following statements is NOT correct?

a.

The curve that depicts the differences in agency efficiency can be calculated by subtracting the transaction costs when production is organised through an arm's-length market exchange from the transaction costs when production is vertically integrated.

b.

The curve that shows differential efficiency is a vertical summation of the curve that reflects differences in agency efficiency and the curve that reflects differences in technical efficiency.

c.

The curve that depicts the differences in technical efficiency can be calculated by subtracting the minimum cost of production under vertical integration from the minimum cost of production under arm's-length market exchange.

d.

The curve that reflects differences in agency efficiency is positive for low levels of asset specificity.