A: Radula is rasping organ of all molluscs. R: It is made up of vitrodentine.

Options

A. If both assertion & reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both assertion & Reason are true but the reason is not the correct explanation of the assertion, them mark (2).
C. If assertion is true statement but reason is false, them mark (3).
D. If both assertion and reason are false statements, them mark (4).

Explanation

To analyze the statements regarding radula in molluscs, we will break down the assertion and reason step by step.

### Step 1: Understand the Assertion
The assertion states that "Radula is a rasping organ of all molluscs."
- **Analysis**: The radula is indeed a rasping organ found in many molluscs. However, it is important to note that it is not present in all classes of molluscs. Specifically, bivalves (such as clams and oysters) lack a radula and instead use cilia for feeding. Therefore, the assertion is **false**.

### Step 2: Understand the Reason
The reason states that "It is made up of vitrodentine."
- **Analysis**: Vitrodentine is a hard, enamel-like substance found in some fish, particularly sharks, and is not a component of the radula. The radula is primarily composed of a cartilaginous base called the odontophore and other muscle tissues, not vitrodentine. Thus, the reason is also **false**.

### Step 3: Conclusion
Since both the assertion and the reason are false, we can conclude that the correct option is that both the assertion and reason are false.

### Final Answer
Both assertion and reason are false.

---