Which is the function of the cholesterol molecules in a cell membrane

This helps slightly immobilize the outer surface of the membrane and make it less soluble to very small water-soluble molecules that could otherwise pass through more easily. Without cholesterol, cell membranes would be too fluid, not firm enough, and too permeable to some molecules. (www.cholesterol-and-health.com/Cholesterol-Cell-Membrane.html)

Hope this helps

i would go with b

cytokinesis occurs after telophase so that eliminates d

and the entire reason for cytokinesis is for cellular reproduction