Note that this problem is formulated as a p$-$median problem. this formulation ignores the transportation cost between the two hubs. a$)$ Build an alternative model that takes into account the transportation cost between the hubs. Assume that the transportation cost per mile between the hubs is $60\%$ of the cost between hubs and spokes given stated in the book due to economies of scale. Make sure your model includes the following:Sets, parameters, variables defined clearlyMathematical model in closed formA one sentence description of the objective function and each constraint.b$)$ Comment on the complexity of the model in part $($a$).$ Can you revise your model to make it easier to solve?c$)$ Suggest a solution approach for the model in part $($a$).$ Do not solve!