The strength of electric field depends on the distance from the charge and also the distance between the electric field lines. If the electric field lines are closer to each other, the electric field is strong there. closer the electric field lines to each other in a region, stronger is the electric field. Electric field lines are closest in region Y. hence the electric field is strongest in region Y.
In March and September both of the hemispheres receive the same amount of energy from the sun. this is because neither end of the axis is tilted toward the sun.