阅读、理解下面短文并回答81-85题
Means or transportation
There are five major transportation models:highway,railway,pipeline,water and air .The relative importance of each model can be measured in the terms of mileage, load voad volume and cost.
1.Railway
Railway can be used to transport goods with large tonnage over a long distance. Railway companies and operators enjoy the advantage of low operating cost ,such as electricity and fudl.but hace to invest heavily for large fix assets and incur and incur large amount of depreciation and maintenance costs.
2.Highway
Highway transport has developed rapidly since 1970.Highway operations benefits from the ability to transfer goods from virtually door-to-door and operating flexibility which other transportation models can not compete.
3.Water
Water is the oldest means of transportation,and is the most commonly used option for international trades.Cargo ships travel long distance bearing large volumes with very low unit cost .Currently ,acargo ship can load 7,000 containers weighing over 150,000 tons.
4.Pipeline
Pipeline can send goods non—stop,but is restricted to transfer oil and gas.In2003,Chinabegantobuild three pipelines to transport water,calling the operation to“supplement the water in Southern to Northern.”
5.Air
Airfreights are the newest and up—and—coming transportation industry.Although it is of high cost and can be more dangerous,in the long run, air transport will increase its proportion gradually due to the demand for efficiency .
What are the factors of importance measure mode of transportation（）
A．mileage,commodity and cost
B．commodity,time and cost
C．mileage, load volume and time
D．mileage ,load volume and cost