Pair of isobar is :

Options

A. `._(6)^(13)C,_(7)^(13)N`
B. `._(6)^(13)C,_(7)^(14)N`
C. `._(6)^(14)C,_(8)^(15)N`
D. None of these

Answer

To determine the pair of isobars from the given options, we need to understand the definition of isobars and analyze the provided choices accordingly.

### Step-by-Step Solution:

1. **Understand the Definition of Isobars**:
- Isobars are atoms of different chemical elements that have the same mass number (total number of nucleons: protons + neutrons) but different atomic numbers (number of protons).

2. **Analyze the Given Options**:
- We need to check each option to see if they have the same mass number but different atomic numbers.

3. **Evaluate the First Option (Carbon and Nitrogen)**:
- Carbon (C) has an atomic number of 6 and a mass number of 12.
- Nitrogen (N) has an atomic number of 7 and a mass number of 14.
- Since they have different atomic numbers (6 and 7) and different mass numbers (12 and 14), they are **not isobars**.

4. **Evaluate the Second Option**:
- Let's assume the second option is given as two different elements with atomic numbers 13 and 14.
- If we take Aluminum (Al, atomic number 13, mass number 27) and Silicon (Si, atomic number 14, mass number 28), they have different mass numbers, so they are **not isobars**.

5. **Evaluate the Third Option**:
- If the third option consists of elements with different atomic numbers and different mass numbers, they cannot be isobars either.

6. **Conclusion**:
- After evaluating all the options, we find that the only pair that meets the criteria of having the same mass number but different atomic numbers is the first option (Carbon and Nitrogen). However, based on the analysis, they do not qualify as isobars.

### Final Answer:
- The correct pair of isobars is **none of the given options**.