Deon is VP of marketing with a major beverage company and is reviewing the contracts of several film, media, and television personalities who work with the company. Recently, two of them were involved in controversial activities concerning their political beliefs and have been quite vocal regarding several social justice issues. Deon is considering canceling their contracts because it is difficult to establish that their personal views are not the views of his company. Which exchange criteria most directly relates to Deon's cancellation of these sponsorships?

a$.$ Each party is free to accept or reject the exchange offer.

b$.$ There must be at least two parties.

c$.$ Each party believes it is appropriate or desirable to deal with the other party.

d$.$ Each party has something that might be of value to the other party.