The correct option is C Prior to fission
In eukaryotes, the cells divide in M phase (mitotic phase) of the cell cycle which is preceded by interphase.
Interphase has three distinct phases: G1, S and G2 phases.
DNA replication occurs in the S phase.
Therefore, in eukaryotes, the DNA undergoes replication long before its separation in the M phase.
However, in bacteria, DNA replication occurs just prior to fission (division).
Nucleolus is present within the nucleus. Bacteria lack a well-defined nucleus and hence nucleolus is absent. The DNA replication occurs in the cytoplasm of the bacterial cells.
DNA replication occurs in preparation for cell division, while transcription occurs during protein synthesis.