The correct answer is protozoa.
Binary fission is a type of asexual reproduction. It is the most general kind of reproduction in prokaryotes, like bacteria. It also takes place in some kind of single-celled Eukaryotes, protozoa, like Paramecium and Amoeba.
In protists, like protozoa, the binary fission is usually distinguished into types, like longitudinal or transverse, on the basis of the axis of cell separation.