单项选择题
What is the most important marker-related factor to the transport cost?（）
A.Location of market B.Government regulation C.Competition D.Seasonality of products flow
单项选择题 What is the most important product-related factor to the transport cost?（）
单项选择题 How many product-related factors are there to influence the transport cost?（）
单项选择题 Which mode of transportation is most flexible?（）
