## **Core Concept**
The process described involves changing an optically pure isomer, which is a single enantiomer (either dextrorotatory or levorotatory), into a racemic mixture. This mixture contains equal amounts of both the dextrorotatory and levorotatory forms of a compound. The concept here relates to stereochemistry and optical isomerism.

## **Why the Correct Answer is Right**
Racemization is the process by which an optically active compound, which rotates plane-polarized light in one direction (either dextrorotatory or levorotatory), is converted into a racemic mixture. This mixture has equal amounts of both enantiomers and does not rotate plane-polarized light because the rotations caused by each enantiomer cancel each other out. This process can occur through various chemical or biochemical reactions.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately describe the process of converting an optically pure isomer into a racemic mixture.
- **Option B:** This option is incorrect because it refers to another concept and not to the conversion of an optically pure isomer into a racemic mixture.
- **Option D:** This option is incorrect because it does not accurately describe racemization.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that racemization can significantly affect the pharmacological activity of drugs. Many drugs are administered as racemic mixtures, but the activity resides in one of the enantiomers. For example, the beta-blocker propranolol is administered as a racemic mixture, but the levorotatory isomer is more potent.

## **Correct Answer:** . Racemization