Answer:
The correct answer is option - b. thermometer.
Explanation:
A thermometer is a device that use to find out the temperature or the temperature difference. It has two important parts: one a sensing part that will sense or in which a change occurs with temperature change and other a part that interprets the change in part in numeric value.
The temperature of a liquid can be measured by the glass thermometer, with mercury present in it that sense change.
Thus, the correct answer is option - Thermometer.