Interdependent relationships:
a. are emphasized by buying firms when the purchase is deemed important to the organization.
b. are emphasized by buyers when the complexity is high.
c. are more likely to involve operational linkages.
d. all of the above (a) and (b) only

The correct answer is letter D

Explanation:  Interdependence is a concept that governs the relationships between individuals where, a single individual is able, through his acts, to cause effects, positive and / or negative, in the whole society. At the same time, that same individual, in turn, is influenced by the whole.

the secretary of state, appointed by the president with the advice and consent of the senate, is the president's chief foreign affairs adviser. the secretary carries out the president's foreign policies through the state department and the foreign service of the united states.