A point charge q is placed on the top of a cone of serni-vertex angle $\;\theta\;$ Find the electric flux through the base of the cone

Question

$(a)\;\large\frac{q(1-cos \theta)}{2 \in_{0}}\qquad(b)\;\large\frac{q sin \theta}{2\in_{0}} \qquad(c)\;\large\frac{q(1-cos \theta)}{ \in_{0}}\qquad(d)\;\large\frac{q sin \theta}{2 \in_{0}}$