An electric field cannot accelerate:
A. electrons
B. photons
C. neutrons
D. α-particles

An electric field can accelerate charged particles, such as electrons (A) and \alpha-particles (D). However, electric fields do not directly accelerate neutral particles like photons (B) or neutrons (C) because they have no electric charge. Photons, which are particles of light, travel at the speed of light in a vacuum and do not experience acceleration in the traditional sense. Neutrons are electrically neutral and therefore do not interact directly with electric fields.