16. An important difference between an open-loop and closed-loop card network is that in an open-loop card network (BLJ, pp. 74-75; Kindle, 1298-1306; Mann, p. 20) (BLJ Ch. 5, Roles and the Value Chain) A. only consumers above a certain income level can join B. only banks above a certain size can join C. the issuing, acquiring, and network functions are performed by separate entities D. a single entity performs the issuing, acquiring, and network functions