Which of the following molluscs lacks radula?

Options

A. Pila
B. Pinctada
C. Limax
D. Doris

Answer

To determine which of the following molluscs lacks a radula, we will analyze the options provided and the characteristics of the molluscan classes.

### Step-by-Step Solution:

1. **Understand the Characteristics of Molluscs**:
- Molluscs are a diverse group of animals characterized by a soft body, often protected by a hard shell. They are bilaterally symmetrical, triploblastic, and coelomates.

2. **Identify the Function of Radula**:
- Radula is a unique feeding organ found in many molluscs. It is a rasping structure located in the buccal cavity and is used for scraping or cutting food.

3. **Classify the Options**:
- The options given are:
- A) Pila
- B) Pinctada
- C) Limax
- D) Doris

4. **Determine Which Class Lacks Radula**:
- It is important to note that the class Bivalvia (bivalves) is known for lacking a radula. Bivalves include organisms that have two shells and primarily filter feed.

5. **Identify the Correct Option**:
- Among the options, Pinctada is a member of the class Bivalvia (known as pearl oysters). Since bivalves do not possess a radula, Pinctada is the correct answer.

### Conclusion:
- The mollusc that lacks a radula among the options provided is **B) Pinctada**.