The normal to the curve x = a(cosθ + θ sinθ), y = a(sinθ – θcosθ) at any point θ is such that
(a) it makes angle π/2 + θ with x-axis
(b) it passes through the origin
(c) it is at a constant distance from the origin
(d) it passes through (a(π/2), - a).
