3. Huntsman Associates is considering upgrading its escalator equipment. Machines from vendors A and B have the same output, but have different useful lives and operating costs. A's lasts four years while B's lasts three years. The discount rate for the project is 10%, and the performance for each type of equipment is the same. Costs are given below: t= 0 50 30 A B 1 5 12 2 5 12 3 15 20 4 15 Ignoring taxes and depreciation, and assuming that Huntsman plans to operate the machines into the distant future, which vendor should Huntsman Associates choose