futures contract? 20. Which of the following is NOT a difference between purchasing an option and purchasing a a. The option requires that a premium be paid in addition to the price of the financial instrument b. Owners of options can choose to let the option expire on the so-called expiration date without exercising it. c. The fulfillment of futures contracts is regulated by exchanges, while the fulfillment of options is not d. All of these are differences between purchasing an option and purchasing a futures. 19. The sale of a call option on a stock the seller already owns is referred to as a. a covered call. b. a naked call. c. call on futures. d. futures on options