Final answer:
The membrane of a cell is most permeable to water (H2O). The correct answer is option c.
Step-by-step explanation:
The membrane of a cell is most permeable to water (H2O).
Membranes are freely permeable to water due to their fluid and flexible nature. However, they are impermeable to electrically charged ions like Ca2+, K+, and Cl-
This selective permeability is facilitated by ion channel proteins that allow the movement of specific ions and regulate the concentration gradient between the extracellular fluid and the cytosol.