The process of making soap by the hydrolysis of oils or fats with an alkali is called:
Correct: C
Saponification is the process of making soap. It involves the alkaline hydrolysis of an ester (typically a triglyceride, which is a fat or oil) to produce a soap (a salt of a long-chain fatty acid) and glycerol. Esterification is the formation of an ester, hydrogenation is adding hydrogen to unsaturated compounds, and polymerization is forming large molecules from monomers.