During fertilization, the enzyme which facilitates penetration of the egg by the spermatozoan is:

Options

A. acetylcholoineasterase
B. alkaline phosphatase
C. acid phosphatase
D. hyaluronidase

Explanation

To solve the question regarding the enzyme that facilitates the penetration of the egg by the spermatozoon during fertilization, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the specific enzyme involved in the fertilization process that aids the sperm in penetrating the egg.

2. **Reviewing the Options**: The options provided are:
- Acetylcholinesterase
- Alkaline phosphatase
- Acid phosphatase
- Hyaluronidase

3. **Analyzing Each Option**:
- **Acetylcholinesterase**: This enzyme is involved in breaking down acetylcholine in the synaptic cleft and is not related to fertilization.
- **Alkaline phosphatase**: This enzyme is involved in dephosphorylation processes and is not specifically related to sperm penetration.
- **Acid phosphatase**: This enzyme is involved in various biological processes but does not specifically facilitate sperm penetration.
- **Hyaluronidase**: This enzyme is secreted by sperm and plays a crucial role in breaking down hyaluronic acid, which is a component of the extracellular matrix surrounding the egg.

4. **Identifying the Correct Answer**: Hyaluronidase is known to degrade hyaluronic acid, which helps in the breakdown of the protective barriers around the egg, allowing the sperm to penetrate effectively.

5. **Conclusion**: The enzyme that facilitates the penetration of the egg by the spermatozoon during fertilization is **Hyaluronidase**.

### Final Answer:
**Hyaluronidase**