Answer:
The correct answer would be B. semi-permeable.
Plasma membrane of any cell including red blood cell is semi-permeable in nature as it is made up of lipid bilayer.
It permits the passage of certain substances across the membrane while it blocks other substances.
Gases, small uncharged or non-polar substances such as oxygen, carbon dioxide, et cetera can easily pass through the cell membrane of a cell.
Large or charged molecules such as proteins, sodium ions, potassium ions et cetera can not pass through the cell membrane. They require carrier proteins to pass through the membrane.
