The correct answer is phospholipid / lipids.
All of the pairs represent the combination of macromolecules with their basic units.
In the case of lipids, basic building blocks are free fatty acids, not phospholipids. Phospholipids are a class of lipids composed of two hydrophobic fatty acid "tails" and a hydrophilic "head" consisting of a phosphate group which are joined together by a glycerol molecule.
