Assertion :- Thymine is one of the DNA bases.
Reason : Complementary base of guanosine is thymine.

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

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "Thymine is one of the DNA bases." This is true because thymine is indeed one of the four nitrogenous bases found in DNA, the others being adenine, cytosine, and guanine.

2. **Understanding the Reason**: The reason provided is "Complementary base of guanosine is thymine." This statement is false. The complementary base of guanine (which is the correct term instead of guanosine) is cytosine, not thymine.

3. **Evaluating the Relationship**: Since the assertion is true and the reason is false, we need to determine the correct option based on this evaluation.

4. **Conclusion**: The correct answer is that the assertion is true but the reason is false.

**Final Answer**: The assertion is true but the reason is false.

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