Several Developments Limit the Applicability of Weber's Model

Several developments limit the applicability of Weber's model.They include all of the following EXCEPT

A) not all firms need to minimize transportation costs.
B) the production process is much more complex now.
C) transportation cost is best expressed as a linear function of distance.
D) transportation costs having been declining in the long-run.
E) brainpower has steadily been replacing muscle and machine power.