The molecules in the thermometer's liquid spread apart would cause the liquid in the thermometer to drop.
Option: B
Step-by-step explanation:
When placing a thermometer in liquid to assess temperature of the water. The particles in the thermometer's liquid, which is often mercury, spread and rise, reflecting a boost in thermometer temperature. As hot, the liquid molecules in the thermometer travel faster, allowing them to separate themselves a little more. This contributes in the thermometer being powered up. When cooled, the liquid molecules in the thermometer move more slowly, allowing them to come together a little closer. This leads to motion through the thermometer.