Most Bacteria Live in a Solution That Is Hypotonic Relative

Most bacteria live in a solution that is hypotonic relative to the cytoplasm of the bacteria. The cell wall of a bacterium is a peptidoglycan polymer that is tightly cross-linked. This would therefore function to

A) regulate the flow of most molecules into and out of the bacterial cell.
B) provide a rigid wall that prevents the cell from swelling.
C) provide a rigid wall that prevents the cell from shrinking.
D) confirm a close relationship to plant cells that have a similar structure and live in hypotonic solutions.
E) make all bacteria fairly uniform in metabolic chemistry.