General solution of differential equation: $r \sin \theta\; d\theta +(r^3 -2 r^2 \cos \theta +\cos \theta)dr=0$

Question

$(a)\;r^2(1+ce^{-r})=2 \sin \theta \\ (b)\;r^2(1+ce^{-r})=2 \cos \theta \\ (c)\;r(1+ce^{-r^2})=2 \cos \theta \\ (d)\;r(1+ce^{-r})=2 \sin \theta$