The correct option is A NaOH
NaOH is used in the manufacturing of soaps. This is done by saponification method. In this method, acqueous solution of NaOH will react with the trigylcerides of fat or oil to give soap and glycerol.
Theory
Uses of Sodium hydroxide (NaOH)
1. In the manufacturing of soap, paper, artificial silk, and several chemicals.
2. In petroleum refining.
3. In the textile industries for mercerising cotton fabrics.
4. For the preparation of pure fats and oils.