Consider the maximum flow problem.a.[15 pts]Create an example instance of a maximum flow problem. Your instance should contain9n7 nodes and 17m13 arcs.b.[10 pts]State the feasible set and the objective in words. Explain clearly whether this is a discreteoptimization problem.c.[10 pts]Form the node-arc incidence matrix for your instance.d.[15 pts]Give a feasible(not necessarily optimal) solution to your instance. What is the objectivevalue for this feasible solution?e.[15 pts]Provide an upper boundto the optimal objective value of your instance (without solvingit). Explain clearly your approach in finding an upper bound.