The correct answer is A. Prokaryotes.
Prokaryotes are single-celled organisms that do not have a nucleus or other membrane-bound organelles. They reproduce by binary fission, a process in which the cell divides into two identical daughter cells.
Eukaryotes are cells that have a nucleus and other membrane-bound organelles. They reproduce by mitosis, a process in which the cell divides into two daughter cells that are genetically identical to the parent cell.
Arthropods are a group of animals that includes insects, spiders, and crustaceans. They are eukaryotes and reproduce by mitosis.
Therefore, the only option that is missing mitosis and divides by binary fission is A. Prokaryotes.