Hector parked his SUV in long-term parking while he traveled to China. 100 90 80 70 60 50 40 30 Cost ($) 20 10 10 5 Number of Days What does the slope of the line represent? A Hector's parking fees decreased by $30 each week. B Parking cost a flat fee of $30. C Parking cost $30 per day. D Hector got a $30 discount to park his SUV.