What can be said for electric charge if electric flux assocaited with closed loop is zero ?

The spatial distribution of the electric field due to two charges $(A,\,B)$ is shown in figure. Which one of the following statements is correct ?

The electric field in a region is given $\vec E = a\hat i + b\hat j$ . Here $a$ and $b$ are constants. Find the net flux passing through a square area of side $l$ parallel to $y-z$ plane

What will be the total flux through the faces of the cube as in figure with side of length $a$ if a charge $q$ is placed at ?

$(a)$ $A$ $:$ a corner of the cube.

$(b)$ $B$ $:$ midpoint of an edge of the cube.

Write Gauss’s law and give its expression.

What will be the total flux through the faces of the cube as in figure with side of length $'a'$ if a charge $'q'$ is placed at ?

$(a)$ $C$ $:$ centre of a face of the cube.

$(b)$ $D$ $:$ midpoint of $B$ and $C$.