Please answer the question below:

For the following spline model, what are the knots? y =1.8+2.7x+3.5x* +2.9(x-2)." +0.2(x-2).' -3.7(x-2).' -09(x-4)." +1.1(x-4).'-4.7(x-4)." O 1.8 0 4 O 2 and 4 O None of the above Question 18 To make the following spline model continuous, what action should be taken? y =3+2x+4x* +2.1(x-1).0 +9.2(x-1).'-2.7(x-1)." O No action needed O drop the term 2.1(x - 1)+ O drop the term 9.2(x - 1)' O drop the terms 2.1(x - 1)" and 9.2(x - 1)*