Which one of the following molluscs was formerly used as currency ( money ) ?

Options

A. Dentalium
B. Chiton
C. Oyster
D. Loligo

Answer

To solve the question of which mollusc was formerly used as currency, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify a mollusc that was historically used as currency. Molluscs are a diverse group of invertebrates that include various classes.

2. **Identifying Mollusc Classes**: The main classes of molluscs include:
- Gastropoda (snails and slugs)
- Bivalvia (clams, oysters)
- Cephalopoda (squids, octopuses)
- Scaphopoda (tusk shells)

3. **Reviewing Potential Answers**:
- **Dentalium**: This belongs to the class Scaphopoda and is known as tusk shell. It was not used as currency.
- **Chiton**: This belongs to the class Polyplacophora and was also not used as currency.
- **Oyster**: This belongs to the class Bivalvia and has historically been of high economic value. Oysters were indeed used as currency in some cultures.
- **Loligo**: Commonly known as squid, it belongs to the class Cephalopoda and was not used as currency.

4. **Choosing the Correct Answer**: Based on the analysis, the oyster is the only mollusc listed that was historically used as currency.

5. **Conclusion**: Therefore, the correct answer is **Oyster**.