Equipotential Surfaces

Correct answer: A. Because then potential would change along the surface though it is constant

Explanation: An equipotential surface has the same potential at every point, so the tangential change in potential along that surface is zero. Since the electric field is E = −∇V, it has no tangential component there and must be normal, or perpendicular, to the surface. If a field line were parallel, it would imply a potential decrease along the surface, contradicting its equipotential definition. Hence A is correct; the other statements confuse geometry or incorrectly claim the field vanishes.