The correct answer is C. Mesosome.
A ribosome is a small organelle found in all cells that is responsible for protein synthesis. A mitochondrion is a membrane-bound organelle found in all eukaryotic cells that is responsible for energy production. A Golgi body is an organelle found in eukaryotic cells that is responsible for processing and packaging proteins and lipids. A mesosome is an infolding of the plasma membrane that is found in prokaryotic cells.
Mesosomes are not found in eukaryotic cells because they are not necessary for the function of these cells. Eukaryotic cells have a nucleus and other organelles that perform the functions that mesosomes perform in prokaryotic cells.