please solve this LP model . show the variable, objective and constraints. please show the excel implementation.

Exercise 3 A company has assembly plants for a particular product at Al and A2 to service distribution centers at DCI, DC2, DC3 and DC4. It is considering building at most one further assembly plant at either A3 or A4, with the purpose of minimizing the total operating cost (i.e., assembly cost + distribution cost). The table below shows distribution costs between assembly plants and distribution centres, demand at distribution centres, as well as capacity and assembly cost at each existing and proposed assembly plant. Moreover, should a plant be built at either A3 or A4, it has to have a minmum utilisation of 70% Distribution Cost (S/unit) Assembly Capacity Assembly Cost Assembly Plants DCI DC2 DC3 DC4 (units) ($/unit) 10 13 28 15 45 150 A2 20 16 30 34 60 190 A3 18 27 24 22 50 70 A4 16 11 15 23 50 80 Demand 20 17 33 40 1. Build and solve an Excel model to decide: (1) whether to build a further assembly plant and if so where; (2) how many units should be produced in each plant; (3) how many units should be transported from each assembly plant to each distribution center