A “selectively permeable membrane” is the one that allows only certain ions or molecules through the membrane.
For example, the cell membrane allows only certain small molecules along with it, while excludes the other large and polar molecules, it is a selectively permeable membrane.
The selectivity of a membrane is based on its structure and is very essential for the maintenance of homeostatic conditions.
Thus, the options (a), (b) and (d) are incorrect.
Cell is the basic structural unit of the body. Membrane is a structural component that separates intracellular and extracellular environment by means of plasma membrane. This cell membrane allows movement of material, cargo in and out of the cell, gives protection and communication with external environment. A “selectively permeable membrane” is the one that allows only certain ions or molecules through the membrane.
Therefore, the correct option is – c. selectively permeable.