Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Smart cards and mobile phones are becoming an increasingly popular way to make all sorts of payments. Even now, in Japan thousands of transactions, from paying rail tickets to picking up the groceries, take place every day with customers passing their handsets across a small flat-screen device. And predictions in the world of finance reckon that payments using mobile phones will have risen to more than $50 billion in the very near future.

What's the appeal of e-cash? Compared to cheques or credit cards, it offers the speed of cash, but more so. It takes just one tenth of a second to complete most transactions and as no change is required, errors in counting are eliminateD. Fraud and theft are also reduced and for the retailer, it reduces the cost of handling money. Sony's vision of having a chip embedded in computers, TVs and games consoles means that films, music and games can be paid for easily without having to input credit card details.

And what about the future of the banks? Within their grip on the market, banks and credit- card firms want to be in a position to collect most of the fees from the users of mobile and contactless-payment systems. But the new system could prove to be a "disruptive technology" as far as the banks are concerneD. If payments for a few coffees, a train ticket and a newspaper are made every day by a commuter with a mobile, this will not appear on their monthly credit card statements but on their mobile phone statements. And having spent fortunes on branding, credit-card companies and banks do not want to see other payment systems gaining popularity. It's too early to say whether banks will miss out and if so, by how much. However, quite a few American bankers are optimistiC. They feel there is reason to be suspicious of those who predict that high-street banks may be a thing of the past. They point out that Internet banking did not result in the closure of their high-street branches as was predicteD. On the contrary, more Americans than ever are using local branches. So, whether we'll become a totally cash-free society remains open to contention.

The author mentions the case of commuters in the third paragraph to illustrate ________ .

A. the transferability of the system

B. the modern technology of the e-cash system 

C. the banks' cooperation with credit-card companies 

D. a possible drawback of the system