Assertion :- Ctenophoras are exclusively marine, diploblastic radially symmetrical.
Reason :- They can survive in marine habitat due to property of bioluminiscense and reproduction by sexual mode.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are false.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Ctenophoras are exclusively marine, diploblastic radially symmetrical."
- Ctenophora, commonly known as comb jellies, are indeed found in marine environments, meaning they live in saltwater. They are also diploblastic, meaning they have two germ layers: ectoderm and endoderm. Additionally, they exhibit radial symmetry, which means their body can be divided into similar halves around a central axis.

2. **Understanding the Reason**:
- The reason states that "They can survive in marine habitat due to the property of bioluminescence and reproduction by sexual mode."
- Ctenophores do possess bioluminescent properties, allowing them to emit light, which can be advantageous in their marine habitat. They reproduce both sexually and asexually, which is a common trait among many marine organisms.

3. **Evaluating the Relationship**:
- While both the assertion and reason are true, the reason does not adequately explain why Ctenophoras are exclusively marine and diploblastic radially symmetrical. The assertion is based on their biological classification and structure, while the reason focuses on their survival mechanisms in the marine environment.

4. **Conclusion**:
- Since both the assertion and reason are true, but the reason is not the correct explanation for the assertion, the correct answer is that the assertion is true and the reason is true, but the reason is not the correct explanation of the assertion.

### Final Answer:
The correct option is: **Assertion and reason are true, but reason is not the correct explanation of assertion.**

---