【单选题】Dollars and cents are the basic units of American money. The back of all dollar bills are green (hence 'greenbacks'). The commonly used coins are one cent (penny) ,five cents ( nickel), 10 cents(dime)...
A.
They can act as small change for the-exact bus fares.
B.
There is generally no problem in using them in Canada.
C.
As a basic unit of money, they are gradually gaining in usage.
D.
They may come in handy for pay phones or laundry machines.