A radula is a unique organ for feeding found in :

Options

A. molluscs
B. annelids
C. arthropods
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the radula, which is a unique organ used for feeding. We need to identify which group of animals possesses this organ.

2. **Analyzing the Options**: The options provided are:
- A) Mollusks
- B) Annelids
- C) Arthropods
- D) All of these

3. **Identifying the Correct Group**:
- The radula is specifically known to be a feeding organ found in many mollusks. It is a rasping structure that helps in scraping food and creating depressions in surfaces.
- Mollusks use the radula to drill holes in prey or rasp food from surfaces, which indicates its specialized function in feeding.

4. **Evaluating Other Options**:
- **Annelids**: They do not possess a radula. Instead, some annelids have a feeding organ called a proboscis, particularly in parasitic species.
- **Arthropods**: They do not have a radula either; they have a mouth adapted for their feeding habits.
- Therefore, options B and C are incorrect.

5. **Conclusion**: Since the radula is exclusively found in mollusks and not in annelids or arthropods, the correct answer is option A) Mollusks.

**Final Answer**: A) Mollusks

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