Which of the following most nearly gives the differential equation for all circles with fixed radius and tangent to the x-axis? d) (y±r)²(y')² - y? +2ry = 0 e) (y +r) (y)² – 2y? + 2ry = 0 a) (y tr)?(y")² + (y')² ± 2ry = 0 b) (y+r) (y")² - O)² ± 2ry = 0 %3D c) (ytr)²(y')² + y? ± 2ry = 0 f) None of the choices