None of the choices is an acceptable answer. Light ... as well as all other forms of electromagnetic radiation ... is both. When you run light through an experiment built to detect particles ... such as photoelectric stimulation of electron emission ... the light behaves like a stream of particles. When you set up an experiment built to measure and detect waves ... like reflection, refraction, diffraction, dispersion, constructive and destructive interference ... the light does all of those things too. Scientists would only debate the question if light absolutely positively had to be one or the other, and could not possibly be both. Such a debate isn't necessary, and scientists no longer waste their time arguing about it. Light is both. Between Maxwell and Einstein, the wave/particle duality of light had been convincingly demonstrated well over a hundred years ago.