How Has the General Shift from a Manufacturing Economy to a Service

How has the general shift from a manufacturing economy to a service economy in the United States affected physical distribution?

A) Customers require more flexible-yet reliable-transportation service.
B) A very high percentage of the transportation industry's revenues is represented by the traditional high volume shipments.
C) The number of large shipments is growing much faster than the number of smaller shipments.
D) The various elements of physical distribution have become independent of decisions made in other areas.