Tantacles are branched and ratractile in

Options

A. Holothuria
B. Cucumaria
C. Echinus
D. All the above.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which organism has branched and retractile tentacles. We need to analyze the options provided to determine the correct answer.

2. **Analyzing the Options**:
- **Holothuria**: This is a genus of sea cucumbers. The tentacles of Holothuria are typically unbranched and not retractile.
- **Cucumeria**: This is a type of sea cucumber known for having branched and retractile tentacles. The oral end of Cucumeria contains a wall of tentacles that are bushy and pinnate, which are used for capturing prey.
- **Echinus**: This refers to sea urchins, which do not have branched and retractile tentacles; instead, they have spines and tube feet.
- **All the Above**: This option suggests that all the listed organisms have branched and retractile tentacles, which is incorrect based on the analysis of the individual options.

3. **Conclusion**: Based on the characteristics of the organisms, the correct answer is **Cucumeria**, as it is the only one among the options that has branched and retractile tentacles.

### Final Answer:
The correct option is **Cucumeria**.

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