Which of the following figures represents the electric field lines due to a single positive charge?

As shown in the figure,at what distance in $cm$ from point $A$ will the electric field be zero?

Two charges $+q$ and $-q$ are situated at a certain distance. At the point exactly midway between them:

Three identical point charges are placed at the vertices of an isosceles right-angled triangle as shown. Which of the numbered vectors coincides in direction with the electric field at the mid-point $M$ of the hypotenuse?

The maximum value of the electric field on the axis of a charged ring having charge $Q$ and radius $R$ is:

Two point charges $+8 q$ and $-2 q$ are located at $X=0$ (origin) and $X=L$ respectively. The net electric field due to these two charges is zero at point $P$ on the $X$-axis. The location of point $P$ from the origin is: