What are the functions of lipids in living organisms?

I- They are the fundamental material of all cell and subcellular membranes.
II- They form the largest energy reserve in organisms.
III- They function as an effective thermal insulator to protect organisms from environmental cold.
IV- They function as hormones of great relevance to human physiology.
V- They have no nutritional function.
a) I, II, and III are correct.
b) II, III, and IV are correct.
c) I, III, and IV are correct.
d) III, IV, and V are correct.