The best model to use is an exponential model. This is because of the exponential increase in each of the y values. A quadratic model would not work because there is not an increasing-decreasing trend in y values. A liberal model would not work either because there is not a constant rate of increase in the y values. 22-5.5 = 16.5. It takes 16.5 units to move 1 x value (from 1 to 2). However, 49.5-22 = 27.5. It takes 27.5 units to move one x value now (from 2 to 3). There is no cost any trend in increasing. Therefore, an exponential model would be most appropriate because of the considerable differences in increasing between 1 x value unit. Hope this helped!