Regarding a reverse-osmosis type freshwater generator using multiple spiral-wound membrane modules, what statement is true?

Correct Answer: Option B — Modules may be piped in series to increase the freshwater purity.

Reverse-osmosis membrane modules are arranged in series to achieve higher permeate quality. By passing the permeate from the first stage through a second stage, the total dissolved solids are further reduced, effectively increasing the purity of the final freshwater product delivered to the ship's potable water storage tanks.