A transportation problem is a linear optimization problem, which seeks to minimize the total costs of shipment of items from certain origins to a number of destinations while fulfilling the requirements of destinations and emptying the origins. The decision variables of this problem are the amounts to be shipped for each origin-destination pairs.

Some transportation problems may be less restrictive; the total supply may exceed aggregate demand. In such a case, a dummy destination must be defined to fictionally absorb an excessive amount of the supply. Thus, the model becomes balanced and fits the general form of the transportation model. Note that a transportation problem has a feasible solution only if the total availability meets all the requirements.

According to these, the correct answer is given in the option C.