Final answer:
The photoelectric effect provides evidence for the particle nature of electromagnetic radiation, supporting the concept of wave-particle duality.
Step-by-step explanation:
The phenomenon that provides evidence supporting the particle nature of electromagnetic radiation (EM radiation) is A) the photoelectric effect. This effect occurs when photons (particles of light) strike a material and electrons are ejected as a result. The photoelectric effect cannot be explained by a purely wave model of light and thus supports the concept of light behaving as particles. This was a groundbreaking discovery that contributed to the development of quantum mechanics and the dual nature of light, known as wave-particle duality.