Among the electromagnetic waves you mentioned, gamma rays are the fastest for sterilizing pathogens. Gamma rays have the shortest wavelength and highest frequency among the waves you listed, which means they carry a lot of energy. This high energy allows gamma rays to penetrate deep into objects and effectively disrupt the DNA or RNA of pathogens, thereby killing them or rendering them unable to reproduce. Due to their high energy and ability to penetrate matter, gamma rays are commonly used in various sterilization processes, including medical sterilization, food irradiation, and decontamination of certain materials.