Pick out the wrong pair :

Options

A. charge-coulomb
B. temperature-thermometer
C. pressure-barometer
D. sp. Gravity-hydrometer

Explanation

To solve the question of identifying the wrong pair among the given options, we will analyze each pair one by one.

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify which of the given pairs is incorrectly matched. Each pair consists of a physical quantity and its corresponding measuring instrument or unit.

2. **Analyzing the Options**:
- **Option 1**: Charge - Coulomb
- Charge is measured in Coulombs (C). This pair is correct.
- **Option 2**: Temperature - Thermometer
- Temperature is measured using a thermometer. This pair is correct.
- **Option 3**: Pressure - Barometer
- Pressure is measured using a barometer. This pair is correct.
- **Option 4**: Specific Gravity - Hydrometer
- Specific gravity is measured using a hydrometer. This pair is correct.

3. **Identifying the Wrong Pair**:
- After analyzing all the options, we can see that all pairs are correctly matched. However, the question asks for the wrong pair, which may imply a misunderstanding in the phrasing of the options.

4. **Conclusion**: Since all pairs are correctly matched, it appears there may have been a misinterpretation in the question or the options provided.

### Final Answer:
There is no wrong pair among the options provided.