[单项选择]It’s almost the end of summer for the first annual contest to choose the best operating monopoly in America. Five contestants are selected. Each exhibits fine monopolistic characteristics and is worthy of serious consideration for the award.
The U.S. Postal Service claims to be the longest-running monopoly and has the distinction of having its control over First Class mail prescribed by the Constitution. The monopoly has preserved large flows of revenues and high wage rates despite studies showing that private companies could carry the mail more efficiently at much lower cost. On the other hand, the position of the Postal Service has been eroded: first, by successful competition on package delivery; second, by the recent entry of express delivery services; and third, and potentially most damaging, by the introduction of the fax machine. Since faxes are bound to supplant(取代) a substantial fraction of First Class letters, the failure to get Congress to classify a fax as First Class
A. Fine monopolistic characteristics.
B. Large flows of revenues and high wage rates.
C. Its control over First Class mail prescribed by the Constitution.
D. The longest-running monopoly.