Answer:
C. Thermometer and barometer
Explanation:
The thermometer and the barometer are both instruments that are used in the weather forecast. The thermometer is an instrument that is providing information about the temperature, being based on mercury, which expends on higher temperature, and shrinking when the temperature is lower. The barometer is an instrument that provides information about the air pressure. It is also an instrument that is based on mercury, with the mercury being squeezed down by the higher air pressure, and going up when the air pressure is lower.
