A finance manager has to select one of the four different suppliers of raw materials. The total cost functions under the four options are given below. Assume the quality of the raw material to be the same, which of the following is preferred by the finance manager? A. y = 550 + 4.47% B. y = 550 + 4.74X O C. y = 550 + 4.9X D. y = 550 + 5.43X