Bacteria reproduce by :
(a) mitosis
(b) longitudinal fission
(c) meiosis
(d) prokaryotic fission

Options

A. mitosis
B. longitudinal fission
C. meiosis
D. prokaryotic fission

Explanation

To solve the question "Bacteria reproduce by:", let's analyze the options provided:

1. **Understanding Bacteria**:
- Bacteria are unicellular organisms that belong to the prokaryotic domain. This means they lack a defined nucleus and other membrane-bound organelles.

2. **Reviewing the Options**:
- **(a) Mitosis**: This is a type of cell division that occurs in eukaryotic cells, where a single cell divides to produce two genetically identical daughter cells. Since bacteria are prokaryotes, they do not reproduce by mitosis.
- **(b) Longitudinal fission**: This term is not commonly used in the context of bacterial reproduction. The correct term for bacterial reproduction is binary fission, which is a form of asexual reproduction.
- **(c) Meiosis**: This is a specialized type of cell division that reduces the chromosome number by half and is used in the formation of gametes in eukaryotic organisms. Bacteria do not undergo meiosis.
- **(d) Prokaryotic fission**: This is another term for binary fission, which is the process by which bacteria reproduce asexually. In this process, a single bacterial cell divides into two identical daughter cells.

3. **Conclusion**:
- The correct answer is **(d) prokaryotic fission**, as it accurately describes the method by which bacteria reproduce.

### Final Answer:
Bacteria reproduce by **(d) prokaryotic fission**.