The correct answer is: A. Nuclear envelope and DNA.
Prokaryotic cells are the simplest type of cell. They do not have a nucleus or any other membrane-bound organelles. Their DNA is not organized into chromosomes, but is instead found in a region of the cytoplasm called the nucleoid. Prokaryotic cells also lack mitochondria, chloroplasts, and other organelles that are found in eukaryotic cells.
Option B is incorrect because prokaryotic cells do have DNA. However, their DNA is not organized into chromosomes, but is instead found in a region of the cytoplasm called the nucleoid.
Option C is incorrect because prokaryotic cells do have DNA. However, they do not have mitochondria. Mitochondria are organelles that are found in eukaryotic cells and are responsible for energy production.
Option D is incorrect because prokaryotic cells do have a cell membrane. The cell membrane is a lipid bilayer that surrounds the cell and protects it from the environment.
In conclusion, the correct answer is: A. Nuclear envelope and DNA.