Term used for the closed ascocarp is

Options

A. apthecium
B. amphithecium
C. endothecium
D. cleistothecium.

Explanation

### Step-by-Step Solution:

1. **Understanding Ascocarps**: Ascocarps are the fruiting bodies of fungi belonging to the phylum Ascomycetes. They are responsible for the production of ascospores.

2. **Types of Ascocarps**: Ascocarps can come in various shapes, including:
- **Apothecium**: Cup-like structure.
- **Perithecium**: Flask-shaped structure.
- **Hystereothecium**: Elongated structure with a slit.

3. **Identifying the Closed Ascocarp**: The question specifically asks for the term used for the closed ascocarp.

4. **Closed Ascocarp Definition**: A closed ascocarp does not have any special openings on the outside.

5. **Correct Term**: The term for the closed ascocarp is **Clestothecium**. This type of ascocarp is entirely enclosed and is an important structure in certain fungi, such as Penicillium.

6. **Conclusion**: Therefore, the correct answer to the question is **Clestothecium**.