None of the options provided directly correspond to a form of nuclear fission. Nuclear fission is a process where the nucleus of an atom splits into smaller nuclei, along with the release of energy. The options listed (gamma decay, beta-plus decay, alpha decay, beta-minus decay) are types of radioactive decay processes, but they do not involve the fission of a nucleus.
If you're looking for the closest related process, nuclear fission itself is often associated with the splitting of heavy nuclei, like uranium-235 or plutonium-239, and not classified among the types of decay listed.
If forced to choose from the listed types, the answer remains that none are correct as a form of nuclear fission.