The pyrimidines of DNA are represented by :

Options

A. uracil and guanine
B. thymine and cytosine
C. adenine and cytosine
D. adenine and guanine

Explanation

To determine the pyrimidines present in DNA, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA**:
- DNA (Deoxyribonucleic Acid) consists of three main components: deoxyribose sugar, nitrogenous bases, and phosphate groups.

2. **Identify the Nitrogenous Bases**:
- The nitrogenous bases in DNA are divided into two categories: purines and pyrimidines.
- The purines in DNA are adenine (A) and guanine (G).
- The pyrimidines in DNA are cytosine (C) and thymine (T).

3. **Analyze the Options Given**:
- The options provided are:
1. Uracil (not in DNA), Guanine (purine)
2. Thymine (pyrimidine), Cytosine (pyrimidine)
3. Adenine (purine), Cytosine (pyrimidine)
4. Adenine (purine), Guanine (purine)

4. **Select the Correct Pair**:
- From the analysis, the only option that includes both nitrogenous bases classified as pyrimidines is option 2: Thymine and Cytosine.

5. **Conclusion**:
- Therefore, the pyrimidines of DNA are represented by **Thymine and Cytosine**.

### Final Answer:
The pyrimidines of DNA are represented by **Thymine and Cytosine**.

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