Any ordinate NP of an ellipse x²/a² + y²/b² = 1 meets the auxiliary circle at Q. Then, the locus of the normals at P and Q is
(a) x² + y² = (a + b)²
(b) x² + y² = (a - b)²
(c) x² + y² = (a² + b²)¹/²
(d) x² + y² = (a² - b²)¹/²