A business spends $3500 to purchase a copy machine. The business also spends $125 per month on maintenance and supplies for the copy machine. What function equation represents the total cost of the copy machine after x months? A. f(x)= 125x-3500 B. f(x)=3500x-125 C. f(x)=125x+3500 D. f(x)=3500x+125