4. Your factory presently uses workers with paint brushes to finish the metal door frames that are your primary product. Three methods of automating this process are under consideration as given in the table below. a) Which will you choose if you MARR is 18% and you use present worth (PW) analysis? You have no idea how long you will need this service. Show your cash flow diagram. b) Before your company writes the purchase order for the paint system selected, it is announced that the production of metal doorframes will be discontinued in 4 years. Assuming that the salvage value is constant at any time after the system is installed, which will you now choose? Your MARR is still 18% and you still use present worth (PW) analysis. Show the cash flow diagrams. 5) You have identified three alternatives for a small project at your plant. Any of the alternatives would save about $30,000 per year in operating costs. Use AW analysis and a MARR of 15% per year to determine which alternative to select