Which of the following machines has the lowest user cost? Machine A costs $15,000 and depreciates at a 25% rate, machine B costs $10,000 and depreciates at a rate of 20%, machine C costs $20,000 and depreciates at a rate of 10%, and machine D costs $17,000 and depreciates at a rate of 11%. The expected real interest rate is 5%. A) Machine A B) Machine B C) Machine C D) Machine ID