a) Given the following assignment matrix of processing costs for four jobs at four machine centres: Machine Centres Job III IV 15 14 12 16 B 23 22 25 24 C 31 34 32 33 D 21 32 44 53 Find an allocation of jobs to the machine centres so that the total processing cost is minimum. (6 marks) (b) Consider a transportation model with m sources and n destinations. Describe briefly how you can resolve the following situations while solving the problem: (i) Total supply is greater than total demand, (4 marks) In case of an allocation resulting to fewer than m+n-1 basic variables, (4 marks) (c) Consider a transshipment model whose optimal tableau you have determined. The total number of units in the model is 500 and there is an allocation of 100 units from a transshipment point (junction), k, to itself. Explain what this means. (6 marks)