The linear model can be assessed by the checking the independent variables having power 1 which shows the linear relationship between x and y. For example, as in the option B, C and D, the power of Xi's is one. Whereas the non linear model has the power for independent variables greater than 1. For example, as in option A the model is a quadratic model because X associated with β2 has a power of a 2.
28 % is actually written as .28 , so it would be written like this , 600 * 28 = 168.00 = for more simplified form it would be , 168 students , hope this helps
