$\mathrm{P}$ is a point on the ellipse $\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1$ and $\mathrm{Q}$ is the corresponding point on the auxiliary circle. If the normals at $\mathrm{P}$ and Q meet in $\mathrm{R}$, then the locus of $\mathrm{R}$ is the circle $\mathrm{x}^{2}+\mathrm{y}^{2}$ is
(a) $\mathrm{a}^{2}+\mathrm{b}^{2}$
(b) $(a+b)^{2}$
(c) $\mathrm{a}^{2} \mathrm{~b}^{2}$
(d) ab