Final answer:
UV radiation is the sterilization method that disrupts the DNA of microbes, thus preventing them from reproducing, by causing the formation of thymine dimers.
Step-by-step explanation:
The method of sterilization that disrupts the DNA of microbes by changing the chemical structure, thereby preventing them from reproducing, is c) UV radiation. This nonionizing radiation causes the formation of thymine dimers in microbial DNA when they absorb UV light, most effectively at a wavelength of 260 nm. The thymine dimers prevent accurate DNA replication, leading to mutations that can ultimately be lethal to the microorganisms. This method is particularly useful for surface sterilization since UV light does not penetrate surfaces or clear through plastics or glass.