In the early days ofthe United States,postalcharges were paid by the recipient and charges varied with the distancecarried.In 1825,the United States Congress permitted local

postmasters to giveletters to mail carriers for home delivery,but these carriers received nogovernment salary and their entire compensation depended on what they were paid

by the recipients ofindividual letters.In 1847,the United States Post Office Department adopted theidea of a postage stamp,which of course simplified the payment for postal

service but causedgrumbling by those who did not like to prepay.

Besides,the stampcovered only delivery to the post office and did not include carrying it to aprivate address.In Philadelphia,forexample,with a population of 150,000,people

still had to go tothe post office to get their mail.The confusion and congestion of individualcitizens looking for their letters was itself enough to discourage use of themail.It

is no wonderthat,during the years of these cumbersome arrangements,private letter-carryingand express businesses developed.Although their activities were only semi-

legal,they thrivedand actually advertised that between Boston and Philadelphia they werehalf-day speedier than the government mail.The government postal service lost

volume to privatecompetition and was not able to handle efficiently even the business it had.Finally,in 1863,Congress provided that the mail carriers who delivered the mail

from the postoffices to private addresses should receive a government salary,and that thereshould be no extra charge for that delivery.But this delivery service was atfirst

confined tocities,and free home delivery became a sign of urbanization.In 1890,of the 75million people in the United States,fewer than 20 million had mail deliveredfree to

their doors.Therest,nearly three quarters of the population,still received no mail unless theywent to their post office.What is the mainidea of the passage?

A.The development ofa government postal system.

B.The increasing useof private mail services.

C.The history ofpostal stamps.

D.The comparison ofurban and rural postal services.