Assertion(A): In sponges, archaeocytes are totipotent.
Reason( R): They give rise to all types of amoebocytes and are self replicating.

Options

A. Both A) and B) are true and the R) is the correct explanation of A)
B. Both A) and R) are true and the R) is not the correct explnation of A)
C. A) is true statement but R) is false
D. Both A) and R) are false

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**: The assertion states that "In sponges, archaeocytes are totipotent."
- **Explanation**: Totipotent cells are those that have the ability to differentiate into any type of cell. In sponges (phylum Porifera), archaeocytes are indeed totipotent, meaning they can transform into various cell types needed for the sponge's functions.

2. **Understanding the Reason (R)**: The reason states that "They give rise to all types of amoebocytes and are self-replicating."
- **Explanation**: Archaeocytes can differentiate into different types of cells, including amoebocytes, which perform various functions in sponges, such as digestion and reproduction. They are also capable of self-replication, which supports the assertion of their totipotency.

3. **Evaluating the Relationship Between A and R**: We need to determine if R correctly explains A.
- **Explanation**: Since archaeocytes can indeed give rise to all types of amoebocytes and are self-replicating, this supports the assertion that they are totipotent. Therefore, R is a correct explanation of A.

4. **Conclusion**: Both the assertion (A) and the reason (R) are true, and R is the correct explanation of A.
- **Final Answer**: The correct option is that both A and R are true, and R is the correct explanation of A.