Which of the following is not correct

Options

A. `(A)/(T) = 1`
B. `A + T = G + C`
C. A + G = C + T
D. None of these

Explanation

To determine which statement is not correct regarding the nitrogenous bases in DNA, we need to analyze the options provided in the question based on Chargaff's rules.

### Step-by-Step Solution:

1. **Understanding Chargaff's Rules**:
- Chargaff's rules state that in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of cytosine (C) is equal to the amount of guanine (G).
- This can be expressed as:
- A = T
- C = G

2. **Analyzing the Options**:
- **Option A**: A divided by T = 1
- This is correct because according to Chargaff's rule, A = T, thus A/T = 1.
- **Option B**: A + T = G + C
- This is also correct because if A = T and C = G, then A + T = C + G holds true.
- **Option C**: A + G = C + T
- This statement is incorrect. According to Chargaff's rules, A + G (purines) should equal C + T (pyrimidines), but this is not a universally valid statement. The correct relationship is A + G = C + T, which is a different assertion than the one presented.
- **Option D**: None of these
- This option implies that all previous statements are correct, which is not true since Option C is incorrect.

3. **Conclusion**:
- The statement that is not correct is **Option C**: A + G = C + T.

### Final Answer:
The option that is not correct is **Option C: A + G = C + T**.