Drives Co. sells portable hard drives. They can sell 600 drives when the price is $75/ drive, and they can sell 720 drives when the price is $45/ drive. If x represents the number of drives sold, determine the following. (a) What is Drive Co.'s revenue function? R(x)= (b) What is the price per drive (in dollars) when revenue is maximized? $ (c) What is the maximum profit (in dollars) made from the sale of these drives if Drive Co. incurs production costs of $165 per drive and has fixed costs of $685 ? $