Which of the Following Is Not an Assumption of a Minimum

Multiple Choice

Which of the following is not an assumption of a minimum cost flow problem?

A) At least one of the nodes is a supply node.
B) There is an equal number of supply and demand nodes.
C) Flow through an arc is only allowed in the direction indicated by the arrowhead.
D) The cost of the flow through each arc is proportional to the amount of that flow.
E) The objective is either to minimize the total cost or to maximize the total profit.