Identify all of the following 4 charge distributions in which the electric field magnitude is equal to zero at the given point:

Any point above an infinite sheet of charge with uniform charge per unit area; Inside a cylinder, when the cylinder is infinitely conducting with a radius R and charge per unit length lambda; A point which is a distance R from an infinite wire, with charge per unit length lambda; A point inside a conducting sphere of radius R, with charge q on the surface.
2, 4