請依下文回答第 20 題至第 25 題 A thin magnetic stripe is all that stands between Americans’ credit-card information and the bad guys.And they’ve been working hard to break in. Banks, law enforcement and technology companies are all tryingto thwart a network of hackers who are swiping account numbers, names and other crucial data used inidentity theft. More than 100 million accounts at Target, Neiman Marcus and Michaels stores were allaffected in recent attacks, starting November 2013.Cards are increasingly vulnerable to attacks in store transactions. Hackers scoop up massive troves ofcredit-, debit- or prepaid-card numbers using malware inserted surreptitiously into the retailers’ checkoutsystems. Hackers then sold the data to a second group of criminals operating in shadowy corners of the web.Not long after, the stolen data was showing up on counterfeit cards and being used for online purchases.The solution could cost as little as $2 extra for every piece of plastic issued. The fix is a securitytechnology used heavily outside the U.S. While American credit cards use the 40-year-old magstripetechnology to process transactions, much of the rest of the world uses smarter cards with the EMV (short forEuropay, MasterCard, Visa), a technology that employs a chip embedded in the card plus a customer PIN toauthenticate every transaction on the spot. If a purchaser fails to punch in the correct PIN at the checkout, thetransaction gets rejected.The cost of a magstripe card is in the dollar range. A chip-and-PIN card currently costs close to $3.Multiple $3 by 5 billion cards in circulation in the U.S. Then consider that there’s an estimated $12.4 billionin card fraud on a global basis. With 44% of that in the U.S., American credit-card fraud amounts to $5.5billion annually. Card issuers find that absorbing the liability for even big hacks like the Target one is stillcheaper than replacing all that plastic.That leaves American retailers pretty much alone the world over in relying on magstripe technology,and leaves consumers vulnerable. Ironically enough, the historical reason the U.S. has stuck with magstripe isthe once superior technology. The nation’s cheap, ultra-reliable wired networks made credit-cardauthentication over the phone frictionless. In France, card companies created EMV partly because thetelephone monopoly was so maddeningly inefficient and expensive. The workaround allowed transactions tobe verified locally and securely.
20 Who are the bad guys mentioned in Paragraph 1?
(A) Bank robbers
(B) Burglars who break into houses
(C) Account hackers
(D) Pickpockets who stole credit cards