Assertion (A): Chargaff's rule is applicable to RNA.
Reason (R): RNA contains deoxyribose sugar in them.

Options

A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A)
B. Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
C. Assertion (A) is true but reason (R) is false.
D. Assertion (A) is false but reason (R) is true.

Explanation

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

### Step-by-Step Solution:

1. **Understanding Chargaff's Rule**:
- Chargaff's rule states that in a double-stranded DNA molecule, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C). This is often summarized as A=T and G=C.
- This rule is based on the pairing of bases in DNA, where A pairs with T and G pairs with C.

2. **Application of Chargaff's Rule to RNA**:
- RNA (ribonucleic acid) is typically single-stranded and contains uracil (U) instead of thymine (T). Therefore, the base pairing is A with U and G with C.
- Chargaff's rule, as it applies to DNA, does not directly apply to RNA because RNA does not have the same base pairing structure as DNA.

3. **Analyzing the Assertion (A)**:
- The assertion states that "Chargaff's rule is applicable to RNA." This is incorrect because Chargaff's rule specifically pertains to the base pairing in DNA, and while there are ratios of bases in RNA, they do not follow the same rules as in DNA.

4. **Understanding the Reason (R)**:
- The reason states that "RNA contains deoxyribose sugar in them." This is also incorrect. RNA contains ribose sugar, not deoxyribose. Deoxyribose is found in DNA.

5. **Conclusion**:
- Since the assertion is false and the reason is also false, we conclude that both the assertion and the reason are incorrect.

### Final Answer:
- Assertion (A) is false.
- Reason (R) is false.