The parametric equation of the circle $x^{2}+y^{2}+p x+p y=0$ is
(a) $\mathrm{x}=\frac{-\mathrm{p}}{2}, \mathrm{y}=\frac{-\mathrm{p}}{2}$
(b) $\mathrm{x}=\frac{\mathrm{p}}{2} \cos \theta, \mathrm{y}=\frac{\mathrm{p}}{2} \sin \theta$
(c) $x=\frac{-p}{2}+\frac{p}{\sqrt{2}} \cos \theta, y=\frac{-p}{2}+\frac{p}{\sqrt{2}} \sin \theta$
(d) $\mathrm{x}=\frac{\mathrm{p}}{\sqrt{2}} \cos \theta, \mathrm{y}=\frac{\mathrm{p}}{\sqrt{2}} \sin \theta$