The correct option is C Plasma membrane
Bacterial cells are primitive cells hence, called as prokaryotic cells. They do not possess many membrane bound organelles as mitochondria, lysosomes etc. They also do not have well-defined membrane-bound nucleus. Hence, processes, which are carried out by such specialized organelles are carried over by plasma membrane of bacteria. Plasma membrane is a living membrane that forms the boundary between a cell and its environment. Some invaginations of the plasma membrane are called as mesosomes. In bacteria, they are involved in respiration. Mesosomes are also known to help in the separation of two daughter molecules of DNA during cell division. Besides, they also secrete some extracellular substances, which are necessary for their survival. Thus, the correct answer is option C.