The production department is proposing the purchase of an automatic insertion machine. It has identified three machines and has asked the accountant to analyze them to determine which one has the best cash payback. Machine A Machine B Machine C BE I Annual cash flow $40,000 $50,000 $75,000 Average investment 300,000 250,000 500,000 C a. Machine B C b. Machine A C c. Machine C d. Machines B and C have the same preferred payback period.