The formation of an optically active compound from a chiral molecule is called:

Options

A. Asymmetric syntesis
B. Resolution
C. Walden inversion
D. Epimerision

Explanation

To solve the question regarding the formation of an optically active compound from a chiral molecule, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Key Terms**:
- **Chiral Molecule**: A molecule that has non-superimposable mirror images, meaning it can exist in two forms (enantiomers) that are mirror images of each other.
- **Optically Active Compound**: A compound that can rotate plane-polarized light due to the presence of chiral centers.

2. **Identifying the Process**:
- The question asks about the formation of an optically active compound from a chiral molecule. This implies that we are looking for a process that involves the creation of new chiral centers or the rearrangement of existing ones.

3. **Evaluating the Options**:
- **Asymmetric Synthesis**: This is a process where a chiral molecule is transformed into another chiral compound, often resulting in the formation of enantiomers or diastereomers in unequal amounts.
- **Resolution**: This refers to the process of separating racemic mixtures into their enantiomers, not the formation of new chiral centers.
- **Walden Inversion**: This is a specific type of reaction where the configuration at a chiral center is inverted, but it does not necessarily involve the formation of a new chiral compound from a chiral molecule.
- **Epimerization**: This is the process of converting one epimer into another, which involves a change at one specific chiral center, but does not generally refer to the formation of a new compound.

4. **Conclusion**:
- Based on the definitions and the processes described, the correct answer to the question is **Asymmetric Synthesis**. This process involves the formation of an optically active compound from a chiral molecule by introducing new elements of chirality.

### Final Answer:
The formation of an optically active compound from a chiral molecule is called **Asymmetric Synthesis**.