Vertical integration is relatively more attractive:

a. When the ability of outside market specialist relative to the firm itself to achieve scale or scope economies is limited.

b. The smaller the scale of the firm's product market activities

c. The greater the extent to which the assets involved in the production are relationship-specific

d. Only answers 'a' and 'c' are correct

e. Answers 'a', 'b', and 'c' are correct