Eight point charges, each of magnitude q, are located on the corners of a cube of edge length s as shown in the figure below. (a) What is the magnitude of the electric field at the center of the cube? (b) If the charge at point A is removed, what is the magnitude of the electric field at the center of the cube? (c) If the charge at point A is removed, what is the x-component of the electric field at the center of the cube?