Parabola a can be represented using the equation (x + 3)2 = y, while line b can be represented using the equation y = mx + 9. isabel determines one solution to the system of two equations must always pass through the vertex of parabola a. which best describes the reasonableness of her solution? a: isabel is correct because the y-intercept of line b is (0, 9) and the value of y when x = 0 in parabola a is 9. b: isabel is correct because the y-intercept of line b is (9, 0) and the value of x when y = 0 in parabola a is 9. c: isabel is incorrect because the point of intersection between line b and parabola a that can be determined is the y-intercept of the functions, not necessarily the vertex. d: isabel is incorrect because the point of intersection between line b and parabola a that can be determined is the x-intercept of the functions, not necessarily the vertex.