Concept:Soap making depends on the reaction between oil (a fat) and an alkali.
Explanation:Palm oil is a triglyceride, which is an ester of glycerol and fatty acids.
Boiling it with a strong base breaks the ester bonds in a process called saponification.
The liquid extract of ash contains soluble metal carbonates or hydroxides, such as potassium carbonate, which act as a source of alkali.
This alkali reacts with the oil to form soap and glycerol.
Without an alkaline medium, saponification cannot occur, so the ash supplies the required alkali.
Answer:The correct option is
C. Alkali.