The right answer is contains the maximum number of hydrogen atoms.
A saturated fatty acid is a fatty acid having carbon atoms fully saturated with hydrogen (see figure). Each carbon carries as many hydrogens as possible. We can not add hydrogen to the molecule: it is saturated.
All the bonds between the carbons are simple (no carbon-carbon double bonds).
Saturated fats, a type of lipid, are triglycerides obtained by reacting three molecules of saturated fatty acids on a molecule of glycerol.