The answer to this is B. The thermometer is mainly used in order to measure the temperature of different objects. People normally use the thermometer to check their current temperature. A temperature that is above 37 is considered to be abnormal. Slightly higher temperatures than 37 Degrees would mean slight fever. People who have a temperature of 40 should get themselves checked immediately.
The thermometer can also be used to measure different chemicals and even the surroundings. There are still some traditional thermometers available but most people prefer the digital thermometers more right now because they are easier to use. Just remember that there are some thermometers that are more accurate as compared to the others.