Answer: D(nucleoid region)
Explanation:
In the diagram below the irregular shaped, supercoiled region, without a membrane, labelled D, surrounded by the cytoplasm of the cell is the nucleiod region that contains the main DNA in bacterial.
The nucleoid region in the prokaryotic cell contains the main DNA material. The nucleoid which means nucleus-like contains the main genetic material in prokaryotic cell, some satellite DNA are found in plasmid is other parts of the cell. Unlike the nucleus of eukaryotic cells the nucleiod lacks a cell membrane. The nucleiod has an irregular shape, and has a circular chromosome.