The correct option is A binary fission
Amoeba can reproduce under favourable as well as unfavourable conditions. In favourable conditions, it usually reproduces by the binary fission and in unfavourable conditions it reproduces by the multiple fission.
Binary fission is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes and occurs in some single-celled eukaryotes like Amoeba also. In binary fission, the fully grown parent cell splits into two halves, producing two new cells.