**Core Concept**
Saponification is a chemical reaction that involves the hydrolysis of fats or oils to produce fatty acids and glycerol. This process is often used in soap making, where triglycerides are broken down into soap and glycerol.

**Why the Correct Answer is Right**
The correct answer is due to the hydrolysis reaction catalyzed by a base, typically sodium or potassium hydroxide, which breaks the ester bond between the glycerol backbone and the fatty acid chains. This reaction is an example of a nucleophilic acyl substitution, where the hydroxide ion (OH-) attacks the carbonyl carbon of the ester, leading to the formation of a new bond between the hydroxide and the acyl group, and the release of the fatty acid and glycerol.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because acid hydrolysis (using a strong acid like HCl) is not typically used for saponification, as it would produce a mixture of fatty acids and glycerol, but not the desired soap product.
**Option B:** This option is incorrect because lipase enzymes are involved in the hydrolysis of fats, but they are not responsible for the saponification reaction.
**Option C:** This option is incorrect because neutralization of fatty acids with a base is not the same as saponification, which involves the hydrolysis of the ester bond.

**Clinical Pearl / High-Yield Fact**
Saponification is an important process in soap making, but it also has implications in the body, as the hydrolysis of fats can occur in the presence of excess base, leading to the formation of soap and glycerol, which can have toxic effects.

**Correct Answer: D. Base (alkali) catalysis.**