单项选择题

Over 60 million persons in the United States own a credit card, which has had the effect of increasing consumption possibilities for households by allowing them to make heavy purchases without giving up a single dollar and coin for than. In fact, thousands of dollars of merchandise, ranging from autos, clothing, to electrical appliances are purchased by buyers through the credit card. Credit cards have also been of significant importance to the national economy. Businessmen have been encouraged to expand plant and equipment and hire additional personnel to meat the heavy demand for their products. The tendency of employ-merit and income would be to rise significantly.
Unfortunately, the ease with which buyers can increase their purchase with credit cards have caused them to overlook the additional costs. Purchases on credit cards are postponed payments. Buy-now-and-pay-later encourages buyers to use credit cards extensively. Since the buyer is in effect borrowing money for a specific purpose, he must expect to pay an interest change. Interest is the price of using money over a long period of time. A close analysis of the use of credit cards for heavy purchases will show that the buyer has added to the cost of making these purchases, it must also be kept in mind that unpaid monthly balance means added interest charges. Furthermore, the use of credit cards will add to the cost of the product since the shopkeeper does not receive the money at the time of purchase. Shopkeeper might add on the cost of handing credits to the bill.
This passage is mainly concerned with ______.