Which of the following could be examples of feedback in an airline's online reserva- tion system? (i) A message asking for confirmation of chosen flight dates, (ii) a link to a web page of an affiliated car rental company, (iii) a page seeking confirmation of payment details, (iv) a message informing the buyer that no flights are available at the chosen time, (v) a pop-up screen, which appears once the transaction is com- pleted, containing the buyer's updated frequent flyer points balance. (a) i, ii, iii, iv (b) ii, iii, iv, v (c) i, ii, iii, v (d) i, iii, iv, v