Two points charges q1 = +1 µC and q2 = – 2 µC are placed at A and B respectively as shown in the figure. The distance between q1 and q2 is 4 cm.

The net electric flux will be zero.

over any surface that encloses a volume including A and B, but having very large radius over any surface that includes A twice and B once over any surface that encloses a volume excluding A and B only over a surface that encloses zero volume

over any surface that encloses a volume excluding A and B

$\phi=\frac{q}{\varepsilon_0}$