Answer:
c. cholesterol
Explanation:
Cholesterol is an amphipathic sterol. It has both polar and non-polar parts that interact with a polar head and non-polar tails of the phospholipids of the plasma membrane. The non-polar steroid nucleus and the hydrocarbon chain of the cholesterol interact with nonpolar tails to make the membranes less fluid at lower temperature conditions. The presence of cholesterol and its interaction with both polar and non-polar components of the phospholipids make the plasma membrane stable.
