A) Quadratic variation. This is because the equation is in the form y = kx^2 with k = 1/8.
B) Inverse variation. Recall that inverse variation is in the form y = k/x which we can solve to xy = k. Here we have k = 9.
C) Direct linear variation. This equation is in the form y = kx, which is also known a direct proportional relationship because k = y/x. In this case, k = 1/11.
