Cephalopod with exoskeleton :-

Options

A. Pila
B. Chiton
C. Unio
D. Nautilus

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a cephalopod that has an exoskeleton. Cephalopods are a class of mollusks that include animals like squids, octopuses, and nautiluses.

2. **Analyzing the Options**: We have four options to consider:
- **Option 1: Pila** - This is a freshwater snail and does not belong to the cephalopod class.
- **Option 2: Chitin** - This term refers to a structural component found in the exoskeletons of arthropods and is not a cephalopod.
- **Option 3: Euneo** - This is a type of freshwater mussel, which again is not a cephalopod.
- **Option 4: Nautilus** - This is a well-known cephalopod that possesses an external shell, which is considered an exoskeleton.

3. **Identifying the Correct Answer**: After analyzing all the options, it is clear that the only cephalopod with an exoskeleton is **Nautilus**.

4. **Conclusion**: Therefore, the correct answer to the question "Cephalopod with exoskeleton" is **Option 4: Nautilus**.