Show that for the transportation model, although the inverse basis is unique, the vector
of basic objective coefficients need not be so. Specifically,show that if Cij is changed to
cij + k for all i and j, where k is a constant, then the optimal values of Xij will remain the
same. Hence, the use of an arbitrary value for a dual variable is implicitly equivalent to
assuming that a specific constant k is added to all Cij"