Chapter 12 - Parametric Equations, Polar Coordinates, and Conic Sections - 12.3 Polar Coordinates - Preliminary Questions - Page 617: 1

(a)

Since the points P and Q have the same radial coordinate, this tells us that they belong to the same circle (because the radius is the same). Thus, points P and Q with the same radial coordinate lie on the same circle with the center at the origin. So (a) is the right answer.