Which of the following mollusc is formed by a larvae which have torsion

Options

A. Lamelledes
B. Pila
C. Sepia
D. Octopus

Answer

To solve the question "Which of the following mollusc is formed by a larvae which have torsion?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand Torsion**: Torsion is a developmental process in which the visceral mass and the shell of the mollusc rotate 180 degrees with respect to the head and foot. This is a characteristic feature of certain molluscs, particularly gastropods.

2. **Identify the Class**: Torsion is primarily associated with the class Gastropoda within the phylum Mollusca. Gastropods are known for this unique developmental process.

3. **Examine the Options**: The options provided are:
- A) Lambladies
- B) Pilla
- C) Sepia
- D) Octopus

4. **Classify the Options**:
- **Lambladies**: This is not a commonly recognized name in molluscs, but if it refers to a type of mollusc, it is likely not a gastropod.
- **Pilla**: This is a type of gastropod, which means it undergoes torsion during its larval development.
- **Sepia**: This refers to cuttlefish, which belong to the class Cephalopoda and do not undergo torsion.
- **Octopus**: This also belongs to the class Cephalopoda and does not exhibit torsion.

5. **Conclusion**: Since Pilla is the only option that belongs to the class Gastropoda, it is the correct answer. Therefore, the mollusc formed by a larvae which have torsion is **B) Pilla**.

### Final Answer:
**B) Pilla**