Which of the Following Is Likely to Limit the Extent

Which of the following is likely to limit the extent of a firm's vertical integration?

A) a managers' bounded rationality
B) a small minimum efficient scale of producing inputs relative to the firm's input requirements
C) the fact that the quality of inputs is easily determined at the time of purchase
D) the presence of a large number of suppliers of the firm's inputs
E) a high transaction cost of contracting with resource suppliers