A device to measure liquid pressure is

Options

A. Thermometer
B. barometer
C. manometer
D. lactometer

Explanation

To determine the device used to measure liquid pressure, we can analyze the options provided:

1. **Thermometer**: This device is specifically designed to measure temperature. Therefore, it is not suitable for measuring liquid pressure.

2. **Barometer**: A barometer is used to measure atmospheric pressure. It does not measure liquid pressure, so this option is also incorrect.

3. **Manometer**: A manometer is a device specifically designed to measure the pressure of liquids. It is commonly used in various applications to determine the pressure exerted by a liquid in a container or system.

4. **Lactometer**: A lactometer is used to check the purity of milk, not for measuring liquid pressure.

Based on the analysis of the options, the correct answer is:

**The device to measure liquid pressure is the Manometer.**

### Step-by-Step Solution:
1. **Identify the options**: The question provides four devices: thermometer, barometer, manometer, and lactometer.
2. **Evaluate each device**:
- Thermometer: Measures temperature.
- Barometer: Measures atmospheric pressure.
- Manometer: Measures liquid pressure.
- Lactometer: Checks the purity of milk.
3. **Select the correct device**: Since the manometer is specifically used to measure liquid pressure, it is the correct choice.
4. **Conclude the answer**: The device to measure liquid pressure is the manometer.