For All Routes with Positive Flows in an Optimized Transportation

Multiple Choice

For all routes with positive flows in an optimized transportation problem,the reduced cost will be:

A)  zero 
B)  how much less shipping costs would have to be for shipments to occur along that route 
C)  how much more shipping costs would have to be for shipments to occur along that route 
D)  how much the capacity is along that shipping route