（）is the Internet commerce designed for direct communications and commercial relationship between a firmand its end customer.

A.freightforwarders
B.shipper＇sassociations
C.insurancebrokers
D.transportationbrokers

A.knowledge
B.materials
C.images
D.CPU

A.fireandtheft
B.unqualifiedproducts
C.techniqueproblem
D.andevennaturaldisasters