A charge Q is placed at the corner of a cube electric flux through the cube is

Question

$(a)\;\large\frac{Q}{6 \in_{0}}\qquad(b)\;\large\frac{Q}{8 \in_{0}}\qquad(c)\;\large\frac{Q}{\in_{0}}\qquad(d)\;\large\frac{Q}{3\in_{0}}$